This is a visualization based on on synaesthesia. (see README-syna).

This implementation is taken from alsaplayer: http://www.alsaplayer.org/ It
is based on synaesthesia version 1.3 (or maybe 1.4, I'm not entirely
certain), with some modifications by Richard Boulton to try and ensure that
something interesting is displayed for both very quiet and very loud music.

Note: only one instance of this plugin may be created at a time: it has a
lot of static data.  This should be fixed (and it shouldn't be hard to do
so, either).