Ok, probably the last version (at least for a while). I can’t think of
much else cool to do. 
The new version of my “explosions” demo includes three new effects:
Blur (average pixels every frame)
Dissolve (randomly remove pixels)
Heat (similar to blur; a “fire,” “burn,” or “flame” effect)
It’s also completely commented.
ftp://ftp.sonic.net/pub/users/nbs/unix/x/explosions/
-bill!