Mike Traynor replied on Philofractal list:

Thanks for sharing those images, especially 69b. It is one of the most beautiful images of any kind, fractal or other, I've ever seen. Wow doesn't begin to cover it.

Brian Prentice wrote on Philofractal list:

...

Very interesting formula Jim, here are three more details:

http://linuxenvy.com/bprentice/Fractals/Set%2013/BP_13_69a.png http://linuxenvy.com/bprentice/Fractals/Set%2013/BP_13_69b.png http://linuxenvy.com/bprentice/Fractals/Set%2013/BP_13_69c.png

Yes, "BP_13_69b" is very good indeed!!! Great coloring choice. :-) And "BP_13_69c" is the second best of these.