Leo Schwab was, along with
R.J. Mical one of my
idols growing up.
He was a master of Intuition, the Amiga's stellar graphics subsystem, and his claim to fame among other things was a whole series of Amiga demos later to become known as "Schwabbies" among the community.
Two great Schwabbies I can think of off the top of my head are one that created a little robot that would walk
on to your desktop, tracking your mouse movements as you went, eventually carrying your mouse pointer off screen, and another more full length demo that lampooned IBM in a Robotron 2048 spoof - and if you gave it the correct secret command line option would end with "Amiga: No Bullshit, just great technology" or something like that. (Note any old time Amiga veterans care to help fillin the details here? My memory is getting worse with age :)
One of the things that made the Amiga great was that it was SO thoroughly hackable, and Leo exploited this all the way :)
He has a web page at http://www.best.com/~ewhac/ but unfortunately there isn't much there about his old
demos, still it's worth a look though.