TEXT: A Scenario for Delta Green: The Role-Playing Game
  THE LAST EQUATION
  A Scenario for Delta Green: The Role-Playing Game
  THE LAST EQUATION
  
  The Mathematics of Murder
  A killing spree is horrifying enough. When all eight members of the Ridgeway fam-
  ily are gunned down by a math student who then kills himself, Delta Green sees 
  hints that make it more terrible still. Your Agents have to stop the madness before it 
  spreads.
  The Last Equation is a full-color scenario of personal apocalypse and lethal mys-
  tery. It is playable with Delta Green: Need to Know or Delta Green: Agent’s Hand-
  book, available from Arc Dream Publishing.
   available from Arc Dream Publishing.
  DELTA GREEN: THE LAST EQUATION
  MSRP $14.99
  Stock code APU8117 • ISBN 978-1-940410-33-3
  Published by Arc Dream Publishing
  Sold by Studio 2 Publishing
  Get more great games at www.arcdream.com.
  This is a work of fiction.
  The Mathematics of Murder
  A killing spree is horrifying enough. When all eight members of the Ridgeway fam-
  ily are gunned down by a math student who then kills himself, Delta Green sees 
  hints that make it more terrible still. Your Agents have to stop the madness before it 
  spreads.
  The Last Equation is a full-color scenario of personal apocalypse and lethal mys-
  tery. It is playable with Delta Green: Need to Know or Delta Green: Agent’s Hand-
  book, available from Arc Dream Publishing.
   available from Arc Dream Publishing.
  DELTA GREEN: THE LAST EQUATION
  MSRP $14.99
  Stock code APU8117 • ISBN 978-1-940410-33-3
  Published by Arc Dream Publishing
  Sold by Studio 2 Publishing
  Get more great games at www.arcdream.com.
  This is a work of fiction.
  
  1
  The Last Equation
  A Scenario for Delta Green: The Role-Playing Game
  Written by Dennis Detwiller
  Published by Arc Dream Publishing in arrangement 
  with the Delta Green Partnership. The intellectual 
  property known as Delta Green is ™ and © the Delta 
  Green Partnership, which has licensed its use here. The 
  contents of this scenario are © 2018 by Dennis Detwill-
  er, excepting those elements that are components of the 
  Delta Green intellectual property. Illustrated by Dennis 
  Detwiller, © 2018. This is a work of fiction. Dedicated 
  to Mark McFadden, the Lizard King.
  Introduction
  Brussels-born mathematician, sage and astronomer 
  Fascius Claudan (1535–1561) was responsible for 
  many minor breakthroughs in science and technology 
  during his short but broadly travelled life. Between 
  journeys to Egypt, Persia, central Asia and more exotic 
  locales, Claudan published six books on astronomy 
  and mathematics. His last book was on cosmology, a 
  book which is considered dangerous by some who know 
  of such things: the Libri Plures Admiratio (“Book of 
  Many Wonders”).
  Claudan is fleetingly remembered as a minor in-
  ventor or various knots, pulley systems, cogworks and 
  early machines for pumping water, but he has vanished 
  almost entirely from known science. One legacy of Clau-
  dan remains: the Laqueus Equation. This short code was 
  rendered just days before his death. It is regarded in the 
  small circles that know of it as either an epiphany or 
  complete gibberish. To date, no one has publicly claimed 
  to understand it, much less to have solved it.
  For over 500 years, the world’s most brilliant math-
  ematicians and cryptographers tried in vain to solve the 
  equation. It holds a place in the annals of cryptography 
  as one of the few cryptograms to resist modern attempts 
  at cracking. It is used as an example in many cryptogra-
  phy tomes as a “clean” cypher, because it has remained 
  untranslatable.
  Until now.
  
  2
  // The Last Equation //
  // Delta Green //
  The Program Makes the Call
  When the report reached the national crime database, 
  the numbers spray-painted on the pavement in front of 
  the Ridgeway murder scene triggered a troubling alert 
  in the Program’s intelligence office. It was flagged as 
  a possible paranormal event. (If your Agents are part 
  of the Outlaw conspiracy and not the Program, then 
  an unnamed Friendly recognized the dire import of 
  the numbers.)
  The numbers have been seen at various times and 
  in various dangerous books known to the conspiracy, 
  once at the death scene of a Delta Green agent. It is 
  high on the containment protocol list as a dangerous, 
  infectious meme.
  The numbers are: 9 9 2 0 .2 2 9 9 8 9 2 1 2 .3 3 3.
  Within an hour, a team is being assembled through 
  secure channels to get to the Ridgeway murder scene. 
  Wherever they live, tickets are waiting to fly them to 
  Newark Liberty International Airport, about 30 minutes’ 
  drive from Alliance, New Jersey.
  Odd Questions
  Reaching out to each Agent in turn, the Agents’ case 
  officer or primary contact asks strange questions before 
  informing them of the assignment: things like “Do you 
  have any experience in theoretical mathematics?” and 
  “On a scale of 1 to 10, how well would you say you 
  understand physics?”
  Any Agent who has any skill in Science (Mathemat-
  ics) or Science (Physics)—unless the skill is unknown to 
  the Program—is told that the case is not for them, and 
  then the contact hangs up. The player should take a 
  temporary replacement character. (As Handler, you can 
  facilitate this by having a couple of spares ready. Delta 
  Green: Agent Dossiers may be useful.) The Program is 
  looking for people to identify and contain the meme, 
  not spread it.
  Some Agents might answer “No” to the above 
  questions while the true answer is a resounding “Yes!” 
  Don’t worry. Having such a character join the operation 
  won’t ruin the scenario, but it might derail things—
  in a fun way.
  Columbia University
  On October 12, Michael Wei, a graduate student in 
  mathematics at the prestigious Columbia University 
  Department of Mathematics, successfully cracked the 
  Laqueus Equation.
  Using a computer program of his own design, Wei 
  examined all seven of Fascius Claudan’s books and 
  discovered a cypher embedded in imperfections on the 
  pages on the last one. That dictated the proper way to 
  decipher Claudan’s last equation.
  What Wei discovered was a complex formula, which 
  rendered the world at every level down to a mathemati-
  cal simplicity never before seen. It was literally a reduc-
  tion of the entirety of existence through prime numbers 
  unlocked in a particular calculation of a sequence of 
  sixteen digits. It revealed a vast and roiling reality danc-
  ing just behind modern mathematics.
  Elated, Wei forwarded this discovery to a very select 
  few on a privately maintained mathematics mailing 
  list. The list consisted of twelve mathematicians known 
  to one another through academia or friendship, math-
  geeks@listbrain.com.
  Wei did this before the true horror of the Laqueus 
  Equation had settled in his consciousness.
  Four hours later, Wei drove out of New York City 
  to Teaneck, New Jersey, and purchased ammunition 
  for a stolen shotgun. He drove 10 km to Alliance, New 
  Jersey. At 2:28:13 P.M., he entered the home of Dinah 
  and Malcolm Ridgeway and their six children. Wei, who 
  had no criminal history, slaughtered the Ridgeway fam-
  ily one by one. He chased the last, 18-year-old Michael 
  Ridgeway, out onto Highway Six and shot him in the 
  back in front of eyewitnesses.
  Before police arrived, Wei spray-painted a number 
  sequence on the pavement as witnesses understandably 
  kept their distance. He then shot himself in the face 
  with the shotgun, removing almost all of his head in one 
  blast. When the police arrived, they had an interstate 
  murder-suicide with nine bodies and no apparent con-
  nection between the victims and assailant.
  No clues, no leads, no motive. All they had was a 
  dead mathematician, the corpses of eight slaughtered 
  innocents, and a spray-painted number.
  As usual, that’s where Delta Green comes in.
  
  3
  // The Last Equation //
  // Delta Green //
  course the Program cannot come forward to assist any 
  of its personnel caught in such a situation.
  A tandem approach is probably the safest, if the 
  Agents think to propose it. One or more Agents can 
  be officially placed on the case as “experts,” while the 
  rest act as a “go team” to investigate leads leaked by 
  their insiders.
  Experts on the Case
  It is generally easy to place an Agent or Friendly as a 
  specialist on the Ridgeway case, as it now falls within 
  the FBI’s jurisdiction (due to Wei’s interstate transpor-
  tation of firearms to commit murder). The murderer 
  killed himself after killing the family, so the local police 
  are eager to close the case and move on, but the FBI 
  wants to confirm that Wei was not involved in anything 
  broader-reaching.
  Joining the Investigation
  The Agents’ case officer assumes that they will join the 
  interstate murder investigation in an official capacity. 
  The Program is well suited for arranging that, and sends 
  the Agents under the aegis of the FBI as special agents 
  or as consultants under an FBI contract. An official tie 
  to the investigation has many advantages, including easy 
  access to crime scenes, witnesses and evidence. 
  Of course, it also brings the Agents under the close 
  scrutiny of the commander of the investigation and has 
  a chance of exposing their real purpose. The Agents may 
  wish to set up a secret, parallel investigation with part of 
  their team or even all of their team. That reduces day-to-
  day exposure to law enforcement officers, but it can be 
  dangerous. Being caught inside a secure crime scene and 
  tampering with evidence carries a heavy penalty (three 
  to five years in prison under New Jersey law), and of 
  Operation IAPETUS Briefing Summary
  You are to investigate the murders of MALCOLM RIDGEWAY (age 44), DINAH RIDGEWAY (43), MICHAEL 
  RIDGEWAY (18), CLARK RIDGEWAY (16), DEAN RIDGEWAY (14), MARY RIDGEWAY (13), ALICE 
  RIDGEWAY (12), and CLAIRE RIDGEWAY (10) in Alliance, New Jersey, on October 12.
  The murderer was MICHAEL WEI (26, deceased). Wei was a mathemats student at Columbia Universi-
  ty, New York. At the scene, Wei wrote a series of numbers which are known to possess dangerous, paranor-
  mal properties.
  Instructions
   
  » Determine if WEI distributed the number in any manner besides the crime scene (such as phone, text, 
  social media, or email).
   
  » Locate WEI’s notes and other works on the number and destroy them.
   
  » Destroy the numbers written at the scene and all photographic evidence of them in the hands of 
  the authorities.
   
  » Locate any individuals who have been exposed to the numbers and have mathematics experience and 
  report them to your case officer.
   
  » To establish a cover story for WEI’s actions, link WEI romantically to DINAH RIDGEWAY. Create what-
  ever documents are necessary to make an affair between the two seem likely.
   
  » Once these actions are complete, contact your case officer for further instructions.
  Possible Friendly Contact
   
  » Trooper Thomas Blanet, New Jersey State Police
  
  4
  // Delta Green //
  // The Last Equation //
  Ironically, the most unassuming role for an Agent 
  would be as a mathematics expert brought in to exam-
  ine the numbers, as well as Wei’s work, email and doc-
  uments. Of course, Delta Green is bringing in the exact 
  opposite: people with little skill in mathematics. Still, 
  the role of mathematics specialist is not unattainable, 
  even to someone uneducated in mathematics. Possessing 
  the proper badge and ID is far more important than ac-
  tually understanding mathematics, as far as the bureau-
  cracy of the FBI is concerned. Few FBI agents are expert 
  mathemeticians, so it’s not hard for an Agent to fake it. 
  A “mathematics specialist” can get away with saying a 
  series of numbers “are gibberish, they mean nothing.” 
  No federal agents or cops on the scene will know to say 
  otherwise, at least for now.
  Paperwork and ID
  The Program sends the proper paperwork and ID to 
  Agents assigned officially to the investigation. Agents 
  with the appropriate backgrounds—those who are 
  already federal law enforcement officers—are suddenly 
  assigned to the Ridgeway/Wei case, and their day-job 
  supervisors are not told why. The whole thing strikes 
  everyone as political, so the Agents’ colleagues encour-
  age them to keep their heads down and finish as soon as 
  possible to avoid trouble.
  Agents without the proper background each receive 
  a FedEx envelope filled with a disturbingly detailed 
  dossier of a new identity. This “cutout” is as real as you 
  can be on paper, at first glance, right down to dental re-
  cords, IRS returns for the last two years, and credit card 
  receipts. It also has the appropriate law enforcement ID, 
  and details on what firearm to purchase as an appropri-
  ate duty weapon. However, this identity will not stand 
  close scrutiny for long. Anyone examining this paper-
  work at length can make a Bureaucracy roll. Success 
  means some inconsistency has been detected. It is then 
  only a matter of time until that thread unravels the false 
  identity. Avoiding that kind of attention is critical.
  Anyone caught illegally posing as a federal officer 
  faces eight to 13 years in jail—even a special agent from 
  a different agency. Anyone outed in such a manner 
  better be prepared to flee. If they don’t, it could mean 
  an ignominious end to a career. Exposed Agents can be 
  readily identified by their fingerprints. If the Agent is in 
  the employ of another agency (for example, if the Agent 
  works for the IRS but is pretending to be with the FBI), 
  each agency will launch an investigation.
  Such a discovery, and possible detainment of an 
  Agent, may make the Program take some unusual steps 
  to prevent a deeper witch hunt from occurring. We 
  leave those details to the Handler. But an Agent who is 
  unfortunate enough to try to crawfish on Delta Green—
  to expose the Program after being left to dangle—will 
  be in for a swift and lethal surprise. Horrific things 
  happen in jail all the time, over things as trivial as a case 
  of cigarettes.
  A Friendly on the Inside
  If the Agents do not officially join the investigation, the 
  Program reaches out to a contact in the New Jersey 
  State Police and gets him placed in the investigation. 
  The last victim and Wei technically died on the highway, 
  which opens the jurisdictional nightmare of the Ridge-
  way murders up to the state police. 
  This contact, Trooper Thomas Blanet, is a 22-year 
  veteran of the New Jersey State Police and a wholeheart-
  ed believer in Delta Green, though he does not know 
  it by that name. Agents he worked with before simply 
  called it “the Group.”
  Blanet has access to most files on the case, as well 
  as crime scene photos, copies of Wei’s hard drives and 
  more. He is careful and resourceful, soft-spoken and 
  to-the-point. Blanet does his best to assist the Agents in 
  retrieving whatever information they need to complete 
  their investigation. He is willing to copy or photograph 
  evidence for the Agents.
  Blanet will not cross certain lines, however. He will 
  not falsify information, tamper with evidence, steal 
  evidence, or tolerate murder or abductions. Agents 
  asking for his assistance in those matters find them-
  selves stonewalled.
  If confronted with an unnatural threat, Blanet acts 
  by the book, never losing his cool unless insanity strikes.
  Blanet brings with him a bit of baggage. His in-
  volvement with the Group dates back nearly 20 years 
  
  5
  // The Last Equation //
  // Delta Green //
  Official Investigators: Ambushed
  If any Agents are officially placed on the case, the fol-
  lowing occurs just as they arrive at either the airport or 
  at Alliance, New Jersey, itself.
  As an Agent exits a vehicle, he or she is ambushed 
  by a small press team: reporter Enrico Savé (see THE 
  FACE OF NORTHERN NEW JERSEY on page 9), a camera-
  man, and a producer. The camera shines a bright light 
  in the Agent’s eyes as the reporter launches a barrage 
  of questions that vaguely imply that the case’s investi-
  gators are keeping the truth to the public. The reporter 
  already knows the Agent’s name (or at least the name on 
  the Agent’s credentials), and bombards the Agent with 
  questions about Wei and his motives.
  If the Agent has a Charisma of 13 or better, the 
  player must make a Luck roll. If it fails, that Agent be-
  comes the “face” of the investigation in the eyes of the 
  media. (If there are two or more Agents with Charisma 
  13 or better and only one is female, she gets the honor. 
  Otherwise it goes to the one with the highest Charisma.)
  If that happens, other news agencies now go out of 
  their way to track down this particular Agent and in-
  terrogate him or her with ambush interviews. God help 
  the team if this comes to pass while they are involved in 
  something unnatural, because a camera crew is likely to 
  be nearby, looking for trouble.
  Worse yet, if that Agent has been assigned a false 
  identity to pursue the investigation, every time he or she 
  appears on the news, the player must make a Luck roll. 
  If it fails, someone recognizes the character as a video 
  spreads through Twitter, Facebook, YouTube, cab-
  le news, and so on. The character may suddenly get a 
  phone call asking what he or she is doing in New Jersey 
  and why he or she was identified by the wrong name on 
  the news. If the Luck roll is a fumble, someone in the 
  character’s own office saw the broadcast and the Agent’s 
  official supervisor is informed. It’s then only a matter of 
  minutes until the hammer falls.
  to the locally infamous Tiem slaughter, a hit on a dozen 
  men of Vietnamese extraction by an unknown gang. 
  Blanet claimed he was struck on the head and did not 
  recall any of the particulars of the firefight that erupted. 
  Investigators said Blanet froze in the line of duty, which 
  cost Alliance Police Officer Morris O’Dell his life. Blanet 
  was cleared, but it put him on the radar of local news. 
  He was later diagnosed with and treated for post-trau-
  matic stress disorder. 
  Blanet will do his best for Delta Green. His maneu-
  vering would be easy if the Ridgeway murders were an 
  abstract little news story. For about the first ten minutes, 
  it was. It’s not anymore.
  Preliminary Plans
  Smart Delta Green Agents will immediately secure a 
  primary base of operations and, if they are particularly 
  diligent, a secondary safe house. Alliance, New Jersey, is 
  nothing more than two strips of restaurants, gas sta-
  tions and some large shops, surrounded by sparse lots 
  that once were farms. Two large motels sit on the east 
  and west of town and a hotel stands in the center of the 
  strip. The Motel 6, on the west side, is the current haunt 
  of all manner of law enforcement personnel; it would 
  be the common choice of an FBI specialist, and, most 
  likely, a room is waiting for any official member of the 
  investigation.
  Killer Math Teacher!
  By the time the Agents are in the air from their various 
  ports of call, the story of Wei’s murder of the Ridge-
  way family has become national news. Reporters have 
  descended on Alliance, New Jersey, in droves. The story 
  is filled with the hooks that make viewers tune in by the 
  millions: insanity, murder, innocents slain, and a confus-
  ing back-story which may never be understood. Already, 
  camera crews are camping out at every meaningful place 
  in Wei’s life or the lives of the Ridgeways. They are like-
  ly to be anywhere the Agents arrive, and they are likely 
  to have lots of questions. This makes the investigation 
  doubly dangerous. Conspiracies don’t have a good track 
  record of surviving encounters with the press.
  
  6
  // Delta Green //
  // The Last Equation //
  Special Agent Gant
  William Gant is Canor’s go-to man. He is young and 
  eager, working his way up the ladder at the Garret 
  Mountain office. He both looks up to Canor and covets 
  his position. Everyone at Garret Mountain knows Gant 
  is on the fast track.
  Gant is a short, stocky, dark-haired Caucasian, only 
  31 years old. His eyes are a deep green and seem too 
  close together. At first glance this makes him look stupid. 
  He’s anything but. He dresses in carbon-copies of the 
  same suit every day—always charcoal grey—along 
  with a pair of tinted sunglasses. He projects a feeling of 
  careful routine.
  Gant has a close-knit family with many siblings, 
  nieces and nephews. He has been on the prowl for a sig-
  nificant other for a long time now, but he’s a bit out of 
  practice. This becomes evident whenever Gant is dealing 
  with a woman about his own age. His somber attitude 
  immediately becomes overly jovial instead.
  Gant graduated Quantico six years ago and is still 
  relatively wet behind the ears. He was a marvel as a 
  student, and is still known to instructors at the acade-
  my—some of whom are Delta Green operatives. 
  Gant is deeply religious (Greek Orthodox) and be-
  lieves in unseen things. He dislikes only one thing about 
  Canor: his lack of faith in any religion. Gant’s father 
  often said, “Never trust an unreligious man,” and to a 
  certain degree that distrust is evident in Gant’s relation-
  ship with his supervisor. Gant has never really taken to 
  Canor as much as Canor has taken to Gant.
  Bringing Gant into Delta Green is a viable option, 
  particularly if the Agents approach him through Del-
  ta Green operatives at Quantico who were once his 
  teachers. If exposed to the conspiracy in such a manner 
  (or more likely, to the fact that the government has a 
  supernatural investigation arm), Gant will do anything 
  to be a part of it.
  Dr. Comox
  If the Agents do not think ahead and fill the slot of FBI 
  mathematics specialist with one of their own, the FBI 
  sends one who is truly expert. Anyone familiar with the 
  mission protocols can immediately see this as a problem.
  The Ridgeway Investigation
  The following characters might turn up in the investiga-
  tion of the Ridgeway murders. Use them as you will.
  Supervisory Special Agent Canor
  Aiden Canor is a 15-year veteran of the FBI, assigned 
  to the Garret Mountain Resident Agency in Woodland 
  Park, New Jersey, a short drive from Alliance. He has 
  been the lead investigator of nine investigations in the 
  last four years, successfully prosecuting six of them.
  Canor is a 47-year-old African American man, tall 
  and thin, with steel-rimmed aviator sunglasses, always 
  clad in black a suit. He lives with his wife and two chil-
  dren in Bergen, New Jersey. He is a straight-laced agent 
  with no substantial dirt in his past.
  Canor is an easy-going supervisor who places his 
  trust in those who prove themselves. He is easy to get 
  along with, as long as the Agents are careful to go above 
  and beyond when Canor asks them for information. If 
  the Agents fail him, or avoid direct questions by him, 
  Canor becomes interested in them as a “manpower 
  problem” and inserts himself in their lives to find out 
  “what’s wrong.” 
  Canor’s interest in helping the Agents to help the in-
  vestigation can be very, very bad. The Agents might find 
  Canor at their hotel doors late in the evening to “catch 
  a beer” and “discuss their problems.” Needless to say, 
  the last thing any Agent needs is face-time with the FBI’s 
  lead investigator.
  Canor will not believe in the unnatural under 
  nearly any circumstances. He views even direct experi-
  ence of magical effects with disdain, as some complex 
  shuck and jive. His mind just does not feature such a 
  possibility. 
  If the Agents attempt to bring Canor into Delta 
  Green, it becomes readily apparent that it was a large 
  mistake. If Canor discovers the conspiracy, nothing 
  short of a direct, unequivocal threat to his family will 
  disengage him. And a threat like that turns him into an 
  enemy for life. He then makes a career of uncovering 
  Delta Green and bringing the Agents to justice.
  
  7
  // The Last Equation //
  // Delta Green //
  Day 2
  Comox walks through the crime scene at the house, and 
  stops in the kitchen, where a large portion of the mur-
  ders happened. She stares at the damaged stove. Anyone 
  watching her sees the color drain from her face. She 
  hurriedly leaves the scene. If questioned, she replies, “I 
  just thought of something,” but does not say what. She 
  remains in her room for the rest of the day.
  Day 2: If Comox Is Interrupted
  If Comox is approached about the numbers on Day 2, 
  it is clear she is deeply disturbed about something. She 
  says that Wei was brilliant but deranged, and that his 
  math is so complex, she’s not sure she can fully un-
  derstand it. To those with a mathematics background, 
  she talks of number series, strange interrelationships 
  between number sequences, and reoccurring patterns in 
  prime numbers.
  This is the point of no return for Comox. If she 
  is removed from the investigation here, and all her 
  notes are removed, she will take a leave of absence and 
  slowly recover.
  Day 3
  Comox stands at the highway near the Motel 6, look-
  ing at her watch. She holds a pen and a notepad. She 
  seems engaged in some sort of count. Every once in a 
  while a car passes, she checks her watch, and she notes 
  something down.
  After one hour and twenty-three minutes of this, 
  she seems satisfied and retires to her room. If she is 
  interrupted, it seems as if she’s been crying, but her 
  attitude is jubilant, almost manic. If asked what she 
  was doing, she says she was “testing a theory” without 
  explaining. She is not seen again outside of her room 
  that day. She phones the scene supervisor and complains 
  of indigestion.
  Day 3: If Comox Is Interrupted
  It is clear Comox is off the rails. If detained, she contin-
  ues to degenerate, and will never recover. She attempts 
  to escape and fulfill her Day 5 plans.
  Dr. Sarah Comox is a crypto-analyst for the FBI, 
  with a double Ph.D. in mathematics and cryptography. 
  She has worked on several cases involving mathematical 
  oddities. Comox is a 46-year-old Caucasian woman 
  with sandy brown hair cut in a bob, a chubby face, and 
  little in the way of grooming. She would not look out 
  of place at an insurance seminar. She looks over-dressed 
  in her business suit. Her demeanor practically screams 
  T-shirts and sweat pants.
  Comox has no family to speak of and few friends.
  Above all, Comox is a maven for numbers. She is in 
  great danger.
  She will, of course, have access to the sequence 
  of numbers found at the crime scene, as well as Wei’s 
  notes from his dorm. It is a matter of time before she 
  realizes that Wei broke the Laqueus Equation, and that 
  the solution may be the greatest discovery in all mathe-
  matics history.
  Those with direct access to her (that is, Agents 
  on the inside of the investigation) notice the change 
  very quickly. 
  Comox’s Timeline
  Here’s a rough schedule of Dr. Comox’s involvement in 
  the operation. Adjust it as needed for your game.
  Day 1
  Comox takes extensive notes at the crime scene, down-
  loads Wei’s email correspondence from the FBI secure 
  servers, and retires to her room at the Motel 6 to study 
  them. The next morning, she is exhausted and sluggish, 
  looking as if she had little sleep.
  Day 1: If Comox Is Interrupted
  If Comox is approached about the numbers by anyone 
  with HUMINT, Medicine, or Psychotherapy at 50% 
  or higher, they see signs of stress and fatigue. If ques-
  tioned about the meaning of the numbers, she seems 
  torn. They could, she finally admits, be very significant, 
  but she is still studying them. She offers nothing more 
  on the subject.
  
  8
  // Delta Green //
  // The Last Equation //
  Laqueus solution to be a threat. If you need an alterna-
  tive, though, one of the other FBI agents or even one of 
  the New Jersey State Police troopers could be substitut-
  ed as being “infected” by the meme, acting out in the 
  manner just described.
  Police Chief Upton Weeks
  Weeks is a career officer, recently named chief of the 
  tiny Alliance Police Department. He is eager to hand off 
  the investigation of the biggest crime in Alliance histo-
  ry to the FBI or the New Jersey State Police. He wants 
  nothing to do with it—not that he’ll say that out loud. 
  Weeks has training in investigations, but offers little help, 
  deferring to his deputies and the FBI.
  Weeks is a 41-year-old Caucasian male with a tall, 
  thin build and a strangely protruding gut. When deal-
  ing with anything investigation-related he has a look of 
  constant confusion about him; that kind of thing is what 
  his deputies are for. It’s only in front of large crowds 
  or cameras that the reason for Weeks’ success comes to 
  light. He has a way with words. He is self-deprecating 
  and humorous, and knows what to say and when.
  Weeks is a family man with two children, and his 
  wife Emily is known as a bit of a battle-axe. For the last 
  year and a half, Weeks has not-so-quietly been sleeping 
  around with an Alliance waitress, Cicely Brown, age 25. 
  This scandal has been on a slow boil for months and 
  could explode at any time.
  His biggest concern is keeping his job. He wants to 
  stay near enough to know what is going on (and maybe 
  take some credit), and far enough out to point a finger if 
  things go wrong.
  Special Agent Canor is smart enough to include 
  Weeks in press events and to paint the chief in a 
  positive light. That makes Weeks Canor’s puppet in 
  nearly every way.
  Trooper Thomas Blanet
  A New Jersey State Police officer, this Delta Green 
  Friendly is useful in many capacities, not the least of 
  which is knowledge of the lay of the land, both liter-
  ally (he has driven around this region for more than 
  20 years) and jurisdictionally speaking. Blanet has 
  Day 4
  Comox fails to report in, and a state trooper is dis-
  patched to her room to locate her. The door is unlocked. 
  The ruined remains of her laptop are found scorched in 
  a metal wastepaper basket along with scraps of paper, 
  apparently ignited with lighter fluid on the walkway 
  outside (so as not to set off the fire alarm).
  Her car is still in the parking lot. Her credit cards 
  are unused. This disappearance is reported to FBI head-
  quarters and an alert is set.
  Day 4: If Comox Is Interrupted
  She is beyond help. She appears normal at first glance, 
  but close observation reveals she’s unkempt and has a 
  glazed look. Comox eagerly murders anyone who gets 
  in her way. She holds them at gunpoint while looking at 
  her watch as if waiting for something. After two min-
  utes and 23 seconds, she shoots them in the head.
  Incarcerated, she is a raving lunatic, screaming 
  about the Laqueus Equation. If she escapes, she at-
  tempts her Day 5 plans. Otherwise, she attempts to 
  kill herself.
  Day 5
  Before business hours, Comox turns up at Shaver and 
  Sons, a small stock trading firm on the lower east side 
  of Manhattan (229 9th Avenue East). After passing 
  through three security doors which require either key 
  card or code access and successfully gaining access to 
  a safe, she destroys $2.3 million worth of bearer bonds 
  by setting a fire. The fire soon rages, igniting most of 
  the offices. Comox is found dead by fire crews, on the 
  ground, having fallen nine stories to her death. She 
  has no identification or clues as to her motivation or 
  methods. She died from the fall. It takes New York law 
  enforcement six hours to identify her and notify the FBI. 
  Interestingly, the telephone number of Shaver and Sons 
  is (212) 333-0229, almost exactly a match to part of the 
  Laqueus solution.
  Infecting Others
  Unless one of the players’ Agents is skilled in Science 
  (Mathematics), only Comox is skilled enough for the 
  
  9
  // The Last Equation //
  // Delta Green //
  been involved peripherally in many operations which 
  involved local police and the FBI, and is well-versed at 
  slipping in and out of the cracks in such fragmented 
  investigations.
  Blanet is a 49-year-old, stocky Caucasian man. He 
  works out religiously and his chest and arms are huge. 
  However, this exercise has not removed his ample 
  beer belly. He keeps his salt-and-pepper hair clipped 
  short. He rarely smiles. In or out of uniform, he is ob-
  viously a cop.
  Blanet is divorced and has no children. His ex-
  wife Rosemarie remarried and moved to Los Angeles 
  11 years ago.
  Blanet will assist the Agents as long as it does not 
  compromise his personal integrity or risk his pension. 
  See A FRIENDLY ON THE INSIDE on page 4 for details.
  The Face of Northern New Jersey
  TV reporter Enrico Savé has been the face of northern 
  New Jersey news for a decade and a half. He is part 
  Mexican, part French, and has the classically handsome 
  looks of an aging 1950s movie star. He is loud, abrasive, 
  and driven. He is always eager to chase down any lead, 
  day or night, to make the six o’clock news sing.
  Savé will be the main thorn in the side of the Delta 
  Green investigation into the Wei murder-suicide.
  As many people have discovered before, Savé is ex-
  tremely effective at emotional and social manipulation. 
  Wherever the Agents go, it is likely Savé will be there or 
  has been there. It quickly becomes clear Savé is far too 
  informed not to have someone inside the investigation.
  Savé also has the uncomfortable ability to be three 
  places at once. His producer, Charlie “Chip” O’Con-
  nell, and cameraman Armand Grant often operate 
  independently of Savé, running down leads and quickly 
  getting Savé to locations of importance. All three are 
  in constant phone and text contact. To avoid Savé, it is 
  not enough to just know where he is. All three must be 
  accounted for.
  Savé has already done a deep background check on 
  Wei and the Ridgeways. He thinks that this is simply the 
  act of a deranged mind and wants “candid” footage of 
  the federal agents for extra color. If the Agents are not 
  cautious, he might realize there is far more to the story.
  
  10
  // Delta Green //
  // The Last Equation //
  numbers for letters), bank accounts, and mortgage 
  amounts yields a sum of 9,920,229,989,212,333.
  Any Delta Green Agent with experience in the field 
  should begin to feel that perhaps they’ve jumped in a bit 
  over their head.
  Investigating the Shotgun
  Wei’s murder weapon is a Remington 870 police 
  shotgun, serial number 2022998. It is well oiled and 
  maintained. It holds eight rounds including one in the 
  chamber. The weapon has been fired repeatedly and is 
  covered in Michael Wei’s fingerprints.
  Its serial number indicates it was sold to the state of 
  New York in the summer of 1959, and was relocated to 
  the 24th Precinct in New York City as a utility weapon. 
  As far as the city of New York is concerned, the weapon 
  is still there.
  Checking with the 24th Precinct—the Agents must 
  make a Bureaucracy roll to get the right officer on the 
  phone, or else take a long drive to go there in per-
  son—reveals the weapon is missing. A wooden box that 
  should hold five Remington 870s is missing one. The 
  box itself seems untampered with; its nails are all in 
  place. If the box is dusted for prints, prints consistent 
  with Michael Wei are found all over it.
  Recently—on the day of the murders, in fact—the 
  weapon was one of an allotment of weapons moved 
  offsite while plumbers replaced a pipe in the basement 
  of the 24th Precinct. The weapons were taken out of a 
  storage locker, boxed, and then moved to the precinct 
  parking lot, where a single policeman watched the pile 
  of weaponry for the day as the work was completed.
  At 5:53 P.M., the weapons were moved back down-
  stairs and signed for. Nothing odd was noted.
  The officer watching the weaponry was Sgt. Mar-
  vin Herrera, a 19-year veteran of the NYPD with a 
  sterling record. He is completely innocent of any crime, 
  although at the beginning it may look like he stole the 
  shotgun or sold it on the side. Herrera is convinced of 
  his own innocence, so his response may be a bit more 
  heated than the Agents expect to any accusations. 
  The Ridgeway Crime Scene
  The Ridgeway house is three stories tall plus a basement, 
  built on a quarter acre just on the edge of New Jersey 
  Highway 6. Built in 1924, it was once the main house 
  of a much larger farm, which was long ago split up 
  into lots. There is absolutely nothing unusual about the 
  house or its occupants. They were innocent bystanders.
  Dinah, Malcolm, Clark, Dean, Mary, Alice, and 
  Claire Ridgeway all died in or around the kitchen. 
  Michael Ridgeway, who was upstairs, fled and was 
  killed outside.
  Wei fired 16 times in the house, hitting each 
  victim once, except for Clark whom he shot twice 
  when the first blast failed to kill him. Wei used both 
  slugs and shot. The kitchen is sprayed with buckshot 
  and slug-holes.
  Strangely, Wei also seemed to fire once in the house 
  with no living target. The stove, a 1970s tan and green 
  monstrosity, was struck by buckshot, and the old clock 
  on it is stopped at 2:28:13 P.M.
  Searching the house provides no clues except the 
  clock in the kitchen.
  There is absolutely no connection between Wei and 
  the Ridgeway family.
  The Numbers
  An Agent who looks into the numbers that Wei 
  painted on the street at any length, and compares 
  them with numbers found at the crime scene, may 
  make a Luck roll.
  If the Luck roll fails, the Agent begins to notice the 
  numbers Wei scrawled everywhere. The ruined clock in 
  the Ridgeway kitchen, for instance, stopped at 2:28:13 
  (or 22813)—numbers in the sequence separated by 
  twos. Also, there are sixteen numbers; Wei fired sixteen 
  times. Such strange, disturbing coincidences appear to 
  any Agent who looks for them. License plates, phone 
  numbers, receipt amounts, anything with a number may 
  turn out to resemble the number sequence.
  Adding, dividing, or subtracting numbers reveals 
  stranger connections. For example, totaling the Ridge-
  ways’ Social Security numbers, their license plates (with 
  
  11
  // The Last Equation //
  // Delta Green //
  Herrera claims complete (and truthful) ignorance 
  of the weapon’s disappearance, and initially claims he 
  never left the boxes unattended without trading off with 
  another officer. Shortly thereafter he corrects himself 
  and explains that he did, in fact, step away for a mo-
  ment when a squad car collided with a small dog at the 
  east exit from the parking lot. The dog, which had run 
  from its owner, was killed in the intersection, and sever-
  al officers gathered to see what the commotion was.
  Herrera was away from the boxes for less than 
  seven minutes.
  If the Agents fail to consider it, Herrera offers up 
  the idea that the cameras that record the outside of the 
  building might have recorded what happened.
  As soon as Herrera realizes that the Agents think 
  a murder weapon was part of the lot that he was 
  supposed to watch, he demands a union lawyer to be 
  present for every interview to ensure that he is not going 
  to be subject to prosecution or a lawsuit.
  The Tale of the Tape
  If they keep things cordial with the police, the Agents 
  can examine recordings from the many cameras which 
  observed all entrances and exits of the 24th Precinct 
  on the date of the murders. An Alertness roll spots 
  Michael Wei, recorded by the front entrance camera, 
  waiting across the street 20 minutes before Herrera 
  reports stepping way. Wei stands holding an obvious-
  ly empty gym bag, and checks his watch many times. 
  He suddenly crosses the street to the west parking lot 
  entrance, 15 seconds before a small dog appears on the 
  other camera and is struck by a police cruiser. On the 
  parking lot camera, Herrera stands and heads towards 
  the commotion. Less than five seconds later, Wei walks 
  to the tarps covering the weapon boxes, uncovers them, 
  produces a claw hammer from his bag, pries open a 
  box, removes a Remington 870, and replaces the lid in 
  less than a minute. He restores the tarp before stepping 
  off camera with the shotgun in his gym bag. This took 
  place at 9:21 A.M.
  Herrera returns a few minutes later and sits down 
  in the folding chair once more, unaware that Wei 
  was ever there.
  Columbia University
  Columbia University is an Ivy League school located in 
  Morningside Heights on Manhattan’s Upper West Side. 
  Wei attended the Applied Physics and Applied Mathe-
  matics program as a graduate student. By all accounts, 
  he was a model student.
  The university is extremely forthcoming with law 
  enforcement personnel, revealing any information they 
  have on Wei without hesitation. A public informa-
  tion official is assigned to the Agents. Sandy Beema, a 
  woman in her mid-40s, is responsible for spin control 
  for the PR disaster that Michael Wei represents. She 
  does her best to paint Wei as a troubled, mentally ill 
  individual who simply snapped. She sharply rebukes any 
  implication that Wei’s involvement in mathematics at 
  the university was responsible for his illness. Otherwise 
  Beema is a great resource, walking anyone with the right 
  police or federal credentials anywhere on campus, as 
  well as granting them access to Wei’s dorm and universi-
  ty email account.
  Wei’s Dorm Room
  Wei was housed in a small dorm room in John Jay Hall, 
  a skyscraper-like residence hall located on the campus. 
  John Jay Hall also houses the Fu Foundation School of 
  Engineering and Applied Science, which contains the 
  Applied Physics and Applied Mathematics program.
  Wei chose the room due to its vicinity to his 
  work. He often went downstairs in his pajamas to 
  work in the lab.
  Wei’s dorm is small, modest and messy. It is clear 
  he had little or no social life. Every surface is covered 
  in half-read books (folded open at random points). His 
  bed is nothing more than a futon dropped in the mid-
  dle of the room.
  A single, rickety Ikea desk holds a nondescript gray 
  computer and a cheap monitor. A pile of papers are 
  stacked all over the table. Most are covered in a scrawl 
  that anyone with any level of Science (Mathematics) 
  skill recognizes as differential equations.
  It is clear this room was simply a rest-stop for Wei 
  in his daily routine.
  
  12
  // Delta Green //
  // The Last Equation //
  The Photocopied Book
  A bundle of pages stained with coffee and food, and held 
  together by an orange binder clip, is shoved beneath 
  Wei’s futon. This is a heavily annotated, photocopied 
  English translation of Libri Plures Admiratio (“The 
  Book of Many Wonders”). Wei’s interest in Fascius 
  Claudan began as a simple query into interesting and 
  esoteric encryption and compression methods. He hoped 
  some old trick might either fit the bill for his Mersenne 
  prime algorithm or point the way toward a solution.
  Instead, he found a gaping hole in reality.
  With some effort, Agents can find that the book was 
  photocopied from the Educational Studies Books edition 
  of The Book of Many Wonders, translated by Maurice 
  Ester and published in 1944. The company is long since 
  defunct, and it only published several hundred copies of 
  the book before ceasing publication. All involved in the 
  translation and production are long dead from normal 
  causes. There is nothing sinister about this. The book 
  was not popular, and only now has the study of mathe-
  matics caught up with Claudan’s discovery.
  Before the 1960s, the book posed little threat to any 
  except the most brilliant mathematicians. Now, to any 
  mathematician worth his or her salt, reading this book 
  is like pointing a gun at his or her own head. Anyone 
  with a Science (Mathematics) skill of 20% or more who 
  studies the photocopy is subject to the ill effects as out-
  lined in THE LAQUEUS SOLUTION on page 15.
  The photocopied book is covered in handwritten 
  notes, some coherent, some not. The deadly number 
  sequence covers the last page in a violent scrawl. It 
  appears as if the marker used to scribble it broke during 
  the writing. 
  Notes in the margins in Wei’s handwriting include 
  some disturbing elements. Deciphering this chicken 
  scratch requires a successful Science (Mathematics) roll. 
  If successful, the Agent reading the manuscript realizes 
  that Wei predicted the time the Agent would find the 
  book and read the entry, as well as the Agent’s Social 
  Security Number, age, and the latitude and longitude 
  of the Agent’s home address. There is even a scrawl 
  at the end of the equation which says, “Hello!” This 
  costs 1/1D4 SAN.
  Nothing is obviously unusual in Wei’s apartment. 
  There is no indication he owned any firearms.
  Digging deeper into his digital records and the pa-
  pers on his desk reveals some oddities.
  Wei’s Computer
  The computer is a poorly maintained, component-built 
  machine running a recent version of Windows.
  It is not password-protected and all directories on it 
  are open. There is nothing hidden on the machine.
  Wei’s last email was sent the morning of the murders 
  to mathgeeks@listbrain.com, a group composed of 12 
  mathematics students and teachers from around the 
  world who are interested in mathematical puzzles. This 
  email was the complete and complex solution to the 
  Laqueus puzzle. Anyone with a Science (Mathematics) 
  skill of more than 20% can use this email to “solve” the 
  Laqueus equation. (See THE LAQUEUS SOLUTION on page 
  15 for details.)
  Wei’s Papers
  The papers are of particular interest. Those stacked 
  on top the pile are the most recent and are filled with 
  a spray of complex numbers. The equations seem to 
  resolve in a chain of numbers: 10.12, 921, 40.796901, 
  and –73.968158. They represent the date and time (Oc-
  tober 12, 9:21 A.M.) of Wei’s theft of the shotgun and 
  the  latitude and longitude of the 24th Precinct house 
  (40.796901, –73.968158).
  Anyone putting this together with the video from 
  the 24th Precinct must make a Sanity roll. Failure costs 
  1D4 SAN from the horrors of the predictive power of 
  the equation.
  Furthermore, each Agent with a Science (Mathemat-
  ics) skill of 20% or more must make a Luck roll. If it 
  succeeds, the Agent loses 1D4 SAN as additional ram-
  ifications of the equation’s effects sink in. In addition, 
  from this point on, any time that Agent is exposed to 
  the equation, the number sequence, or numbers generat-
  ed by it, he or she must make another Luck roll or lose 
  another 1D4 SAN. Such a character who hits the Break-
  ing Point comes under the influence of the equation. (See 
  THE LAQUEUS SOLUTION on page 15 for details.)
  
  13
  // The Last Equation //
  // Delta Green //
  mention of him was his incarceration in an alms-house 
  in the summer of 1651. No other record exists for him 
  past this point. Most scholars assume he died, as thou-
  sands did, from an outbreak of cholera which swept 
  through Brussels that summer.
  Only six copies of Libri Plures Admiratio sur-
  vived to the modern age. All but one were lost during 
  World War II. The last, thought to be the original, re-
  sides in Brussels.
  Several small publishing houses have created copies 
  of the book, and a few cryptography books cite the 
  puzzle in it, but for the most part it remains an obscure 
  footnote in scientific history.
  The Mailing List
  The mailing list mathgeeks@listbrain.com is composed 
  of 12 individuals in academia around the world who 
  enjoy puzzles, codes and mathematical ciphers. It is 
  maintained in the open and membership is open to any-
  one (though a moderator ensures no spammers make it 
  on the list). 
  It is a small group and it sees only periodic activity, 
  usually comprising a flurry of emails concerning some 
  puzzle or equation. The latest email was from Michael 
  Wei, containing the complete solution to the Laqueus 
  Equation, on October 12 at 6:41 A.M. No one has 
  responded to this email yet.
  The list moderator is Julio Kimbrel, Ph.D., a 
  professor of mathematics at Alfred University in upstate 
  New York. He is wholly forthcoming with anyone in 
  law enforcement. Luckily, he has not read the Laqueus 
  solution. But he might, especially if the Agents indi-
  cate it might have something to do with the murders 
  in New Jersey.
  The list includes:
   
  » Lawrence Badek, 42, a math and chess enthusiast 
  in Wiesbaden, Germany
   
  » Kelly Casselman, 29, a math teacher in a high 
  school in Brinkman, Montana
   
  » Jamie Izzi, 19, a biochemistry student in 
  Paris, France
  If the Agents’ case officer or Delta Green contact is 
  made aware of this manuscript, they immediately order 
  its destruction, as well as a report on who has read it 
  or is reading it. If they learns that an Agent has spent 
  significant time with the manuscript, the other Agents 
  are tasked with carefully observing the reader.
  Researching Fascius Claudan
  Agents with at least 70% in History—or with at least 
  50% in History and at least 40% in Latin, Dutch, or 
  French; or who gets help from an expert in early-mod-
  ern European history; or who simply succeeds at a 
  History test—can find details about Fascius Claudan in 
  Columbia’s library.
  Fascius Claudan—summarized on page 1—is an ob-
  scure figure in scientific history. He is mentioned in some 
  sixteenth-century texts as an oddity, almost a cautionary 
  tale, and then not at all. His name vanishes from most 
  texts at about the time of the Dutch invasion of England 
  (1688), almost as if it had been purposely excised.
  Claudan was known in Brussels as a brilliant inven-
  tor and scientist. Locally he was held in high esteem by 
  nobles, and his papers were seen as far away as Milan. 
  Early in his career, Claudan focused on astronomy, me-
  chanics, and simple machines. He developed two pulley 
  designs which enjoyed widespread use in Europe. Still, 
  his name was clouded by his later activities.
  Claudan travelled to Asia and Africa and, according 
  to some sources, was corrupted by the influence of for-
  eign science and magic. Upon his return, Claudan was 
  withdrawn and strange; some even called him insane. 
  He defaulted on debts and was thrown in an almshouse 
  more than once. He feverishly wrote a series of books 
  on astronomy, Asian and African-influenced science, 
  and alchemy. In his last book, Libri Plures Admiratio 
  (“The Book of Many Wonders”), Claudan revealed the 
  Laqueus Equation, a math puzzle he claimed he learned 
  from an  Arab in Constantinople in 1650. The book 
  claims this Arab was six hundred years old and had seen 
  the “grand library of Nakotic,” wherein lie the secrets 
  of the ancient architects of the world.
  Claudan’s death remains a mystery. No official 
  records indicate how or where he died. The last official 
  
  14
  // Delta Green //
  // The Last Equation //
  turn reveal odd mathematical structures that hover far 
  above the highest prime identified to date.
  See THE LAQUEUS SOLUTION on page 15 for details.
  Wei’s Friends and Neighbors
  Those who knew Michael Wei are shocked, saddened 
  and sickened by his death and the murders he commit-
  ted. Some simply can’t believe Wei is responsible for 
  such a thing and remain certain he was either co-
  erced or framed.
  Wei was held in high esteem by all in his program. 
  He was known as a hard worker, happy and no-non-
  sense, bent on making math his life. He had many 
  passing acquaintances but few close friends. His closest 
  friends were Anthony Desjardin and Molly Frank.
  Molly and Anthony are graduate students at the Ap-
  plied Science and Applied Mathematics school, and are 
  a couple. The two were good friends with Wei for more 
  than a year, and considered him a “project.” That is, 
  they routinely attempted to set him up with friends. Wei 
  spent many weekends with the two, drinking, talking 
  physics and math, and basically goofing off. 
  The two are absolutely certain that there is no way 
  that Michael Wei could have done the things the author-
  ities claim he did. They vehemently dismiss all evidence 
  to the contrary and say simply: “No. Michael wasn’t 
  wired that way. He was a peaceful guy.”
  Wei’s Family
  The Wei family resides in Alta Mira, California. Com-
  posed of Miriam Wei (Michael’s mother) and Imogen 
  Wei (Michael’s younger sister), the family is literally 
  dumbstruck by the turn of events.
  Michael was always an exceptional student and was 
  the golden child of the family. At the time of his father’s 
  death (eight years ago) Michael was already an accom-
  plished student-mathematician. 
  Michael’s mother has spent the last few days heavily 
  sedated, and Imogen has been attempting to arrange 
  a remote, quiet funeral for her headless and infamous 
  brother. There is nothing to learn from Michael’s family, 
  except that they are devastated and sickened by the 
  turn of events.
   
  » Noreen Kuder, 22, a math student in Ma-
  nila, Philippines
   
  » Tia Markell, 29, a math dabbler in New York City
   
  » Eve Mehaffey, Ph.D., 39, a physicist in 
  Brighton, England
   
  » Ben Philbeck, 44, a computer scientist at Law-
  rence Livermore National Laboratory, California
   
  » Kelly Pletcher, 21, a physics student at the Univer-
  sity of Columbia, Missouri
   
  » Julius Sward, 31, a house-husband in 
  Modesto, California
   
  » Emile Tumlinson, 51, a chemist for Tyson Foods 
  in Miami, Florida
  Asking Delta Green
  Informing their case officer or Delta Green contact 
  about the mailing list before hell breaks loose elsewhere 
  is a mark in good favor for the Agents. The Agents 
  themselves might be dispatched to investigate the nearest 
  list member (Tia Markell in New York City). They are 
  told the others “will be handled.”
  Clever Agents may watch the news to see the effects 
  of the Laqueus solution on the list members. Others 
  might search the Internet for the names on a daily basis, 
  looking for stories.
  Others still might visit those on the list in the hopes 
  of short-circuiting the solution’s effect on them.
  If they ask Delta Green about foreign nationals 
  on mathgeeks@listbrain.com, their contact answers 
  quite frankly: “They’re not your problem. Worry 
  about Americans.”
  Wei’s Last E-Mail
  The solution to the Laqueus Equation, emailed to the list 
  October 12 at 6:41 A.M., is both elegant and disturb-
  ing. To those with no background in mathematics, the 
  solution is simply gibberish. To those with significant 
  Science (Mathematics) skill, the equation is a trap.
  Mathematicians might describe it as a “key” which 
  reveals a chain of prime numbers. These numbers—
  which are “unlocked” in a sequence—show huge and 
  previously unknown prime numbers. These primes in 
  
  15
  // The Last Equation //
  // Delta Green //
  The Shotgun
  The Agents probably want to know how and where Wei 
  obtained a police shotgun. There are no records of Wei 
  purchasing any weapons in the tri-state area, and the 
  gun is registered to the NYPD. See INVESTIGATING THE 
  SHOTGUN on page 10 for further investigation of it. 
  In truth, the Laqueus Equation “told” Wei where to 
  find the gun and what to do with it.
  The Laqueus Solution
  The number-patterns revealed by the Laqueus Equa-
  tion are an extra-dimensional trap, a pinhole through 
  what we know as reality that reveals something be-
  yond, something infinite. This crack in the world is 
  enough to consume any with the mathematical chops 
  to understand the sequence, the chain of numbers, and 
  interrelationships they represent. To those not schooled 
  in advanced mathematics, the numbers remain harmless 
  gibberish, a madman’s last bizarre message to the world.
  Solving the Equation
  Anyone with a Science (Mathematics) skill of more than 
  20% can “solve” the Laqueus Equation with a Science 
  (Mathematics) roll. If the roll succeeds, the character 
  must then make a Luck roll. If that fails, the charac-
  ter begins to see numbers from the sequence every-
  where. The full consequences of the equation will soon 
  be unleashed.
  Choices
  Take aside a player whose Agent is affected by the equa-
  tion. Explain that the Agent has discovered perhaps the 
  most important piece of mathematics in the history of 
  the world. If the universe is a mathematical puzzle, this 
  number sequence is the answer. Ask whether the Agent 
  intends to delve deeper into the numbers or attempts to 
  ignore the sequence.
  Effects
  Whether the Agent chooses to ignore or explore the 
  sequence, he or she loses 1/1D6 SAN once a day as the 
  Agent recognizes its far-reaching implications. Those 
  Wei’s Life
  Michael Wei was not a recluse, but he did not draw 
  much attention. He spent very little money on personal 
  goods, ate mostly in the school cafeteria, and was in 
  the lab working most of the time. His neighbors report 
  nothing unusual, and all had a nodding acquaintance 
  with him. He had few close friends, but spent most of 
  his free time (which was very limited) with Anthony 
  Desjardin and Molly Frank.
  Wei’s life is easily tracked by his credit card and 
  bank card, and it ran like clockwork. Even up until the 
  day of his crime, Wei followed the same routine. Break-
  fast at the cafeteria at 7 A.M., work until 1 P.M., lunch 
  at the cafeteria or the Surly Bean coffee house across 
  campus, work in the lab until 8 or 9 P.M. and then 
  either a pizza at home or takeout food.
  Wei’s real life seems to have been his math, and it 
  is obvious to all who knew him that math was ev-
  erything to him.
  Wei’s Work
  Wei’s school work and dissertation involved research 
  into Mersenne prime numbers: huge prime numbers 
  buried in values so large that they encompass millions 
  of digits each. Wei was working on fast distributed 
  math models to generate extremely large Mersenne 
  primes, numbers somewhere in the range of fourteen 
  million digits.
  He hoped to achieve this through a special, small 
  algorithm which could be run on a personal computer, 
  or a smartphone for that matter. This data could then 
  be dumped and “chewed” by another algorithm to sift 
  for high primes.
  To date, this algorithm remained a failure. Early 
  positive results in his ideas had proven false, something 
  known to all in the program. Wei was extremely forth-
  coming about his work.
  This failure had sent Wei on a search for clever 
  math puzzles and solutions. That led him to Libri 
  Plures Admiratio.
  
  16
  // Delta Green //
  // The Last Equation //
  always involves murder and the eventual self-destruction 
  of the character. Try to take the player aside and involve 
  him or her in the Agent’s self-destruction. It’s fun to go 
  crazy! Tell the player the Agent is in an ever-degrading 
  spiral of mental illness. Then issue the Agent’s “orders” 
  and let the player act it out naturally in the game. 
  An Agent who succeeds at suppressing the disorder 
  can resist the urge to violence but cannot tell people 
  about it. The Agent has no moment of clarity, only an 
  intermission in which to plan rather than act.
  The objective of the end game might be as focused 
  as killing everyone in the Delta Green group, or as 
  far-ranging as murdering the U.S. president on live tele-
  vision. Play the situation out in the game, allowing the 
  player to attempt to accomplish the goal.
  If the player refuses, step up the SAN losses as the 
  character feels the increasing trauma of refusing an over-
  whelming compulsion from the universe itself. When the 
  character hits zero SAN, the equation-given task should 
  be that much more awful.
  Marching Orders
  Issue the affected player orders from the equation. They 
  can be anything violent; the more random, the better. A 
  set of orders might read:
  1. Locate six people with the initials R.A. Kill 
  them. Don’t get caught.
  2. Murder each of them, 15 minutes after the hour 
  or 51 minutes after the hour.
  3. Find the user of the telephone number (212) 
  989-9222. Follow the user home. Kill every-
  one there. Call the local news and repeat the 
  Laqueus solution to them. Pour gasoline on 
  yourself and the corpses. Burn yourself alive.
  If necessary, the Handler should invent new sets of 
  orders. The objective is always horrifyingly violent mur-
  der, with details and victims that seem entirely random 
  except for the numbers, ending with the killer’s suicide. 
  Of course, if an Agent reduces a Bond’s score to zero by 
  projecting the equation’s SAN loss, that Bond could be 
  the first or last victim.
  who reach the Breaking Point are on the fast track to 
  self-destruction.
  Paranoia
  Solving the Laqueus Equation fills a mathematician at 
  all times with a feeling of creeping dread, as if the world 
  itself is closing in. Descriptions of this condition vary. 
  Some describe the empty air as something alive and 
  squirming. Others say that the stars are watching them. 
  There is a constant  feeling of a ubiquitous presence spy-
  ing on their every action. This feeling increases in inten-
  sity as time goes on. In the beginning it can be shrugged 
  off and hidden. As SAN losses increase, it becomes more 
  and more evident in the person’s behavior.
  Detection
  Anyone observing a character affected by the equa-
  tion may make a HUMINT or Psychotherapy roll for 
  each SAN loss the subject has suffered. With a success, 
  the observer recognizes that the subject is suffering from 
  some kind of mental illness. Those who are familiar 
  with the “illness” that the Laqueus Equation seems to 
  produce, and are actively looking for such symptoms, 
  gain a +20% bonus to the roll.
  Chains of Causality
  Those who solve the equation begin to see numbers 
  from the sequence on receipts, in birth dates, in tele-
  phone numbers, on TV, everywhere. They are surround-
  ed by the numbers. If they dig a bit deeper, they discover 
  seemingly unrelated numbers add, subtract, divide and 
  multiply to reveal portions of the sequence.
  Those who explore such numbers soon find the 
  sequence “leading” them to places. This might be as 
  easy as a telephone number being revealed through 
  some math, along with latitude and longitude, and 
  a letter-number replacement code which reads 
  “KILL THEM ALL.”
  End Game
  An Agent who reaches the Breaking Point due to the 
  equation gains a new disorder (“obsession with the 
  Laqueus Equation”) and is in the end game. What task 
  the equation has for the Agent is up to the Keeper, but it 
  
  17
  // The Last Equation //
  // Delta Green //
  Once these orders are issued, encourage the affect-
  ed player to act them out in the most devious, clever 
  fashion possible. Their goals should be primarily to 
  not be caught, and secondarily to carry out the equa-
  tion’s orders.
  Capture
  If an affected Agent is somehow subdued, disarmed and 
  locked up, he or she becomes totally unresponsive unless 
  put into a situation where it’s possible to enact the or-
  ders or spread the number sequence.
  Psychological testing reveals a deep psychosis 
  involving the subject’s perception of being controlled 
  by unseen forces. The subject must do his or her best 
  to spread knowledge of the solution as far and wide as 
  possible, making the character dangerous even under 
  controlled conditions.
  Once the viral nature of the number-meme is 
  confirmed by Delta Green, it won’t be long for unaf-
  fected Agents to be ordered to silence infected individu-
  als permanently.
  Trouble Elsewhere
  Just as the situation in Ridgeway begins to hum, trou-
  ble begins elsewhere. Three additional crime sprees are 
  outlined here. Feel free to expand the death toll using 
  the MathGeeks list as a starting point.
  Modesto Murders
  Two days after the Ridgeway slaughter, a seemingly un-
  related crime occurs in Modesto, California. A family of 
  four dies under suspicious circumstances. Julius Sward 
  (age 31), Anetta Sward (30), Anthony Sward (2), and 
  Evelyn Sward (5) are found in the ruins of their home, 
  which was burned to the ground around them. Each 
  of them had been shot by a small caliber weapon. The 
  weapon could not be located in initial investigation.
  In truth, Julius Sward murdered his family and then 
  burned the house to the ground. As the home burned, 
  Julius shot himself while surrounded by the bodies of his 
  family. The gun, a small .22 pistol, is still in the gutted 
  ruins of the house.
  
  18
  // Delta Green //
  // The Last Equation //
  removed a pump shotgun, leveled the weapon at the 
  nearest student, and asked, “What’s the answer?” When 
  the student failed to properly answer, Casselman blew 
  his upper torso open. This continued until 11 students 
  were dead and the rest had fled. Casselman apparently 
  then shot herself in the chest with the shotgun.
  Casselman seems light years from the type of person 
  who could commit such a crime. Like Wei, she was 
  quiet, bookish, and loved her job. She was a diligent 
  teacher who took care of her students. She was heavily 
  involved in school activities. Students thought fondly of 
  her before the incident.
  That’s five days into the operation. If the Agents 
  somehow find themselves looking for Casselman before 
  her self-destruction, they have a chance to stop the mas-
  sacre. Those showing up at Casselman’s home before the 
  attack find the door open and the living room covered 
  in a bizarre mixture of ripped and arranged pictures, 
  mostly of students at the school. 
  Casselman is oblivious to the Agents, even if they 
  knock. She sits at her computer, entering odd number 
  sequences into a calculator and then entering the results 
  in a spreadsheet. A new shotgun sits on the desk next 
  to her. She does not answer orders or requests, but only 
  continues typing.
  If stopped, Casselman smiles and asks quietly, 
  “What is the answer?” Apart from the shotgun on the 
  desk, she seems totally impassive and unthreatening. If 
  she is not cuffed, or the gun not removed, Casselman 
  suddenly snatches up the shotgun. Resolve the resulting 
  combat as usual. She is a schoolteacher; her physical 
  stats are average and her combat skills are all at base. 
  Nevertheless, Casselman will do her damndest to kill the 
  Agents, one by one, after asking the question “What’s 
  the answer?” 
  If the Agents do not intervene, and look into the 
  case after the massacre, they can find FBI files on Cas-
  selman’s spreadsheet. No one at the local FBI office has 
  realized it, but the fourteen numbers in the spreadsheet 
  correspond to the Social Security numbers of the eleven 
  victims. The other three numbers match students who 
  barely escaped the attack.
  The police are operating under the assumption that 
  the family was attacked by an intruder. It will take some 
  time before they realize Julius was the assailant. No 
  computer or paperwork survived the fire.
  Weisbaden Suicide
  Four days after the Ridgeway murders, a news story 
  makes the rounds of an man threatening suicide at the 
  top of the Marktkirche Cathedral in Wiesbaden, Germa-
  ny. The man, a 42-year-old ex-math teacher named Law-
  rence Badek, has held security forces at bay at the top of 
  the tower for hours, twice unfurling what looks like a 
  bed sheet with numbers written on it in shoe polish.
  The picture of the numbers is very poor. With 
  a Luck or Alertness roll, Agents recognize the La-
  queus solution.
  Seven hours into the incident, it becomes clear that 
  Badek is armed when he ineffectually fires at the police 
  on the ground, hitting no one.
  Finally, a Spezialeinsatzkommando team (the 
  German state police version of SWAT) attempts to take 
  Badek down. The situation ends suddenly with Badek 
  falling to his death along with SDK commando Ernst 
  Austerlitz on live television. The two men tumble nearly 
  two hundred feet and strike a concrete abutment. They 
  die instantly.
  Investigation reveals that Badek was mentally 
  ill. No one locally notices the link to Wei and the list. 
  Badek’s apartment is a crazed assortment of print-outs, 
  dissected books, and maps. The gun, which was owned 
  by a police officer in a nearby town, was reported 
  missing the morning of  Badek’s climb to the top of 
  the cathedral.
  Montana Massacre
  Five days after the Agents arrive at the Ridgeway crime 
  scene, news erupts about a brutal and bizarre attack on 
  a classroom full of students at Lewis and Clark High 
  School in Brinkman, Montana.
  The story is confusing. Nearly a dozen students 
  were killed in a shotgun attack. Survivors claimed their 
  teacher, an unassuming woman named Kelly Casselman, 
  entered the classroom Monday morning with a gym bag, 
  
  19
  // The Last Equation //
  // Delta Green //
  Altering FBI Evidence
  Because the Wei case involves the FBI, case files are 
  copied to the local FBI field office where they are rou-
  tinely digitized and dispatched to FBI headquarters. The 
  Agents might be able to gain access to the local FBI field 
  office to destroy or alter evidence without assistance. 
  But it is nearly impossible for them to gain access to FBI 
  headquarters without some assistance from Delta Green. 
  It remains up to you whether such a mission is under-
  taken by another team, by an insider at FBI headquar-
  ters, or by the Agents themselves.
  Closing the Case
  The best way for the Agents to cover their tracks may 
  be to see to it that the Wei case is quickly closed. This 
  should not be hard. Wei clearly committed the murders. 
  All that really remains is to confirm that he acted alone, 
  and to determine whether the NYPD officer from whom 
  he stole the shotgun should be charged for negligence. 
  The Agents can shut down that part of the investigation 
  by making a convincing argument and succeeding at 
  a Law roll. That results in the case being closed with-
  in a week and everyone—including the Agents—be-
  ing sent home.
  Of course, if anyone outside Delta Green discovers 
  that Wei’s fellow MathGeeks list members have begun 
  killing people, that explodes the case into investigation 
  of an international conspiracy. That official investiga-
  tion is likely to last months, whether or not the Agents 
  manage to contain the numbers. The Agents ought to do 
  everything possible to prevent that.
  Killing the Infected
  Anyone who understands the Laqueus solution is a 
  vector for the “disease.” The Agents’ orders from Delta 
  Green say anyone exposed to the number should be 
  reported to their case officer or contact. If the Agents 
  ask for orders on dealing with an infected individual, 
  they are told brusquely to “remove the vector.” Their 
  contact does not elaborate, but the meaning is clear: 
  Kill anyone exhibiting symptoms of “infection” by the 
  Laqueus solution.
  Containing the Numbers
  The primary motivation of the Agents, once the situa-
  tion is fully understood, should be the containment of 
  the Laqueus solution. This is more difficult that might 
  be initially imagined. By the time the Agents arrive on 
  the scene, the number has already done what it does 
  best—it has propagated into hundreds of files, people’s 
  heads, photographs, and videos. It has even been shown 
  (briefly) on the news.
  Altering Local Evidence
  Agents acting under official authority of the FBI have 
  access to the Alliance Police Department, and have free 
  rein on the case files. However, the chain of evidence re-
  quires those examining such files to sign in and sign out. 
  Destruction of papers, photos, or videos will eventually 
  be noticed. But the tampering is relatively easy and 
  might not be detected at all for a time.
  Agents destroying files must make a Luck roll. On a 
  failure, someone immediately notices the tampering and 
  those who signed in are investigated. Another Luck roll 
  must be made or the Feds are brought in and things turn 
  more serious.
  If the Luck roll succeeds, the tampering goes un-
  noticed for 1D8 weeks. Then, unless the Wei case has 
  been completely closed, it is discovered and investigated. 
  Most likely, by this time the Agents will be long gone, 
  but accusations of tampering with evidence could haunt 
  them even when they think it’s all over.
  Clever Agents could alter evidence rather than 
  destroying it outright. Photos can be replaced with 
  photo-manipulated versions where the numbers are 
  obscured or altered. Reports can be duplicated down 
  to the last detail, except for the Laqueus-related num-
  ber. Replacing such files takes 2D10 hours and requires 
  the Forensics skill, free access to the files, a computer, a 
  printer, and no witnesses. It is up to the Agents to set 
  up this situation. At the end, the Agents must make a 
  Forensics roll; use the highest skill among them. If it 
  fumbles, the tampering is noticed after 1D8 weeks. Oth-
  erwise, they get away with it.
  
  20
  // Delta Green //
  // The Last Equation //
  itself is not well known either to mathematicians or 
  book dealers, but can be found for the right price.
  The original copy of the book itself is contained 
  at L’Université libre de Bruxelles, in Belgium. It is very 
  rarely looked at and has remained untouched in the 
  library for nearly 22 years. Gaining access to the book is 
  as easy as having any lettered teacher in the universities 
  of Europe granting an Agent a letter of introduction. 
  Entry to the private library is far from secure. Agents 
  expecting some vault-like facility will be disappointed. 
  There is only a bored librarian, a small room, and stacks 
  of old books. Destroying the book is easy. If violence en-
  sues, everyone in the library attempts to flee rather than 
  interfering. Destroying Claudan’s original, hand-written 
  code is probably the easiest thing any of the Agents 
  could undertake in this scenario.
  Destroying the original manuscript in this fashion 
  regains those involved 1D4 SAN.
  Destroying all known copies of the book regains 
  those involved 1D4+2 SAN.
  Killing an unarmed person is very hard on the hu-
  man mind. It costs 1/1D10 SAN due to violence, unless 
  the Agent changes his or her mind at the last moment. 
  Standing by while another Agent commits that murder 
  costs 1/1D6 SAN instead.
  Resolution
  The Laqueus solution operates a lot like a virus. It 
  moves from host to host, can lie dormant in the form of 
  writing or data for months, years, or even centuries, and 
  can awaken in an explosion of infection at any time. It 
  is a threat. Depending on the Agents’ commitment to 
  the situation, it might become an obsession. Completely 
  wiping out the number is a practical impossibility. 
  Locating and destroying copies of the various trans-
  lations of Libri Plures Admiratio is possible, though 
  time-consuming. Fewer than 400 copies of the book, in 
  various languages, exist worldwide. Many are not in 
  fact full translations, but short portions of Claudan’s 
  notes reproduced in cryptography textbooks. The book 
  
  21
  // The Last Equation //
  // Delta Green //
  Police Chief Upton Weeks
  Chief of police of Alliance, New Jersey. A charming 
  political operative. White male, age 41.
  Chief Weeks
  STR 10  CON 10  DEX 15  INT 16  POW 8  CHA 16
  HP 10  WP 8  SAN 40  BREAKING POINT 32
  SKILLS: Alertness 40%, Craft (Mechanic) 45%, Driving 50%, 
  Firearms 45%, Law 30%, Persuade 70%, Unarmed Combat 
  55%.
  ATTACKS: Unarmed 55%, damage 1d4−1.
  SIG Sauer P226 pistol 45%, damage 1D10.
  State Trooper Thomas Blanet
  New Jersey State Police trooper and Delta Green friend-
  ly. White male, age 49.
  Trooper Blanet
  STR 13  CON 11  DEX 10  INT 11  POW 9  CHA 11
  HP 12  WP 9  SAN 42  BREAKING POINT 36
  SKILLS: Alertness 50%, Driving 60%, Firearms 54%, Law 35%, 
  Navigation 53%, Persuasion 49%, Stealth 50%, Survival 
  33%, Unarmed Combat 55%.
  ATTACKS: Unarmed 55%, damage 1D4−1.
  Glock 19 pistol 54%, damage 1D10.
  Colt AR-15 carbine 54%, damage 1D12, Armor Piercing 3.
  Enrico Savé
  Television reporter—the Face of Northern New Jersey. 
  Hispanic male, age 41.
  Enrico Savé
  STR 10  CON 12  DEX 12  INT 12  POW 10  CHA 17
  HP 11  WP 10  SAN 50  BREAKING POINT 40
  SKILLS: Alertness 55%, Art (Emotional Interview) 70%, Driving 
  30%, HUMINT 50%, Persuasion 80%, Unarmed Combat 
  57%.
  ATTACKS: Unarmed 57%, damage 1D4−1.
  Characters
  FBI Supervisory Special 
  Agent Aiden Canor
  Veteran FBI agent. African American male, age 47. 
  Special Agent Canor
  STR 15  CON 11  DEX 9  INT 14  POW 11  CHA 10
  HP 13  WP 11  SAN 55  BREAKING POINT 44
  SKILLS: Accounting 31%, Alertness 40%, Bureaucracy 
  50%, Driving 45%, Firearms 60%, HUMINT 60%, Law 
  50%, Persuasion 60%, Search 40%, Stealth 41%, Unarmed 
  Combat 65%.
  ATTACKS: Unarmed 65%, damage 1D4.
  Glock 20 pistol 60%, damage 1D10.
  Special Agent William Gant
  Up-and-coming FBI agent who is ready to believe. White 
  male, age 31.
  Special Agent Gant
  STR 10  CON 12  DEX 9  INT 12  POW 10  CHA 10
  HP 11  WP 10  SAN 50  BREAKING POINT 40
  SKILLS: Alertness 45%, Driving 40%, Firearms 60%, HUMINT 
  50%, Law 51%, Persuasion 40%, Stealth 45%, Unarmed 
  Combat 55%.
  ATTACKS: Unarmed 55%, damage 1D4−1.
  Glock 22 pistol 60%, damage 1D10.
  Dr. Sarah Comox
  FBI crypto-analyst. White female, age 34.
  Dr. Comox
  STR 9  CON 10  DEX 7  INT 15  POW 6  CHA 9
  HP 10  WP 6  SAN 30  BREAKING POINT 24
  SKILLS: Accounting 55%, Alertness 60%, Computer Science 
  60%, Driving 40%, Firearms 40%, HUMINT 40%, Law 35%, 
  Science (Mathematics) 55%, Science (Physics) 30%, SIGINT 
  60%, Unarmed Combat 50%.
  ATTACKS: Unarmed 50%, damage 1D4−1.
  
  KALI GHATI
  A Delta Green operative is missing from a U.S. base in 
  Afghanistan. It’s up to the players’ agents—soldiers, spies or 
  academics with Delta Green clearance—to find him before 
  the disappearance draws the kind of attention that the 
  group cannot afford. Includes six ready-to-play agents.
  ALSO BY ARC DREAM PUBLISHING
  OBSERVER EFFECT
  If we look too deeply into the roiling chaos of reality, chaos 
  may look back. The Olympian Holobeam Array has gone 
  off ine in a catastrophic power surge. Delta Green has 
  reason to suspect the worst. The players’ agents have no 
  idea what they’ll find when they arrive.
  VISCID
  Two days ago, retired geneticist Tibalt Grieves and his 
  girlfriend died gruesomely. A CDC specialist found weirdly 
  unidentifiable samples. When the sun rose, Grieves’ body 
  began to smolder and disintegrate. When the players’ 
  agents arrive, they may find that even death has a half-life. 
  MUSIC FROM A DARKENED ROOM                
  Places, like people, go wrong. In the last 50 years, 18 
  people have died at 1206 Spooner Avenue, and you can 
  feel it. Neighbors stay away. In the hours that stretch like 
  taffy after two, no one hears the music from its darkened 
  rooms. Will the players’ agents be the next to die?
  NEED TO KNOW & HANDLER’S SCREEN
  A 48-page quickstart rulebook has six characters and a 
  starter adventure. A sturdy, full-color game moderator’s 
  screen features and useful tables and data to aid the 
  Handler and evocative art to unsettle the players.
  THE STAR CHAMBER
  A Delta Green operation in Myanmar went disastrously 
  wrong. The players’ agents must interview the team 
  responsible. The action plays out from one conficting point of 
  view to the next. The players must decide who is at fault and 
  who, if anyone, is telling the truth.
  
SOURCE: textdata/thevault/Delta Green [multi]/adventures/DG - Adv - The Last Equation.pdf