of the Doom Editing Utility (DEU) program on the Internet, a program created by Doom fans which made it possible to create entirely new levels. DEU continued development until May 21 of the same year. It was made possible by Matt Fell's release of the Unofficial Doom specifications. Shortly thereafter, Doom players became involved with further enhancing DEU. Raphaël Quinet spearheaded the program development efforts and overall project release, while Steve Bareman lead the documentation effort and creation of the DEU Tutorial. More than 30 other people also helped with the effort and their names appear in the README file included with the program distribution. Yadex, a fork of DEU 5.21 for Unix systems running the X Window System, was later released under the GNU/GPL license. Carmack additionally released the source code for the utilities used to create the game, but these were programmed in Objective-C, for NeXT workstations, and were therefore not directly usable the mass userbase of IBM PC compatible. Jeff Bird is credited with creating the first custom WAD for Doom, called Origwad, on March 7, 1994. Soon, countless players were creating custom WADs and sharing them over AOL, the CompuServe forums, and other Internet-based channels. Many of the WADs were made in the style of the base game, others were based on existing TV series, movies, or original themes. Some of the id Software staff have revealed that they were impressed by some of the WADs. John Carmack later said the following about a Star Wars-themed modification: Another early modification is Aliens TC, a total conversion based on the movie Aliens. Even though WADs modified Doom by replacing graphics and audio, the amount of customization was somewhat limited; much of the game's behavior, including the timing and strength of weapons and enemies, was hard-coded in the Doom executable file and impossible to alter in WADs. DeHackEd, a Doom editing program created by Greg Lewis, addressed this by letting users modify parameters inside of the Doom executable itself, allowing for a greater degree of customization. Commercial WADs Around 1994 and 1995, WADs were distributed primarily through BBSs and via CD collections found in computer shops or bundled together with instruction guides for level creation, while in later years Internet FTP servers became the primary method for obtaining these works. Although the Doom software license required that no profit be made from custom WADs, and Shawn Green objected