fdm is a bit of eye candy for the X Window System. Little lines wiggle around, follow each other, bounce through mazes, and leave pretty trails.

You can download the latest version: fdm-1.392.tar.gz. You can also peruse the source code here.

fdm is part of the xscreensaver package (starting with xscreensaver-3.34, under the name "vermiculate").

Written by me.