It is an analog clock displaying the system-time.
It leverages the new visual features offered by Xorg 6.9/7.0 in combination
with a compositing-manager (e.g. like xcompmgr), gtk+ 2.8.x, cairo 1.0.2 and
librsvg 2.13.93 to produce a time-display with pretty-pixels.

WWW: http://macslow.thepimp.net/?page_id=23