anchor.diff:  
   ==== Problem description
   
  -A cleaner company cleans offices. It and needs to match cleaners and offices in a week.
  +A cleaning company cleans offices. It needs to match cleaners and offices in a week.
   
  -* Each cleaner cleans exactly 1 office per day, together with 2 other cleaners. Those 3 cleaners cleans it entirely during that day.
  -* A cleaner can work with different cleaning colleague's during the week.
  +* Each cleaner cleans exactly 1 office per day, together with 2 other cleaners. Those 3 cleaners clean it entirely during that day.
  +* A cleaner can work with different colleagues during the week.
   * All offices need to be cleaned once by 3 cleaners on the same day. The cleaning company can decide the day of the week.
   * A cleaner travels from his/her home to one office in the morning and travels back in the evening.
   
  -Plan a schedule of the cleaning company for an entire week. Minimize the overall traveling distance of the cleaners.
  +Plan a schedule of the cleaning company for an entire week. Minimize the overall travelling distance of the cleaners.
   
   ==== Assignment
   
  
positive.code: . What is the planning value class(es)?
  . Extra credit: write the DRL score rules in pseudo code.
  
  Presume there's `Location` class with a functioning `long getDistance(Location)` method.
  
  ==== Success criteria
  
  
negative.code: 
  [source,drl]
  ----
  rule "Minimize travelling distance"
  when
     OfficeCleaningSpot($d : office.location.getDistance(cleaner.home)))
  then
  