Description: This produces a ring-like pattern, much like the wood texture, 
Description: but this is a 4D texture. (OK, 3D really, but the third is 
Description: time, not Z).  

Author: Robert Wenzlaff 
Email: rwenzlaff@soylent-green.com
Website: http://www.soylent-green.com
License: GPL

The rings can be assigned a velocity and an 
Description: acceleration.  

Free for use, modification, whatever, as long as this notice
goes with it and no further restrictions placed, yada yada yada, 

See http://www.gnu.org for details.

Description of controls:

	Phase - Starting position of the rings.

	Phase Vel. - The velocity of the rings.  Positive
		values move the rings inward, Neg. Outward

	Vel. Rand - assigns a randomness to the velocity. 
		Rings will not move out smoothly.

	Phase Accel. - Acceleration of rings.  
	 
	Accel. Rand - Randomness of acceleration.  For some reason, 
		Small values cause the rings to break up quickly into
		noise larger values give interesting results.

	Turb Dep - Depth/size of turbulence, causes fraying of edges.
	Turb Siz 

	Thresh - Value of color change.  Determines thickness of ring.

	Hardness - High values cause sharp transition. Low ones
		a soft edge.

TO DO: There are a few combinations of Thresh and Hardness that
	wrap around and give one soft edge, one hard.  I might
	call this a feature, though.


Questions, comments, suggestions to rwenzlaff@soylent-green.com

I would like others to compile and test on various platforms
so I can include pre-compiled versions here.

Thanks and enjoy.