The official Ken's Labyrinth page has the release of the source code for Ken's Labyrinth (thanks Jacek Fedorynski), described on Ken Silverman's Official Home Page as "The first Wolf3D clone." Word on the source is that it "Requires: Microsoft C 6.00A to compiler (NOTE: this is the old DOS 16-bit compiler)." Ken Silverman is the programmer who authored the Build engine that powered Duke Nukem 3D.