Christoph Oelckers (Graf Zahl)

Christoph Oelckers, known more often by his screen name of Graf Zahl (German name of of Sesame Street), is a source port programmer who has contributed significantly to the ZDoom project, including development on his own fork of the codebase known as GZDoom, which is distinguished for its advanced  rendering engine. He played a critical role in the development of DECORATE from its initial restrictions as a simple method for creating static decor objects into the fully featured content definition language which now exists.