Well, I did this before I signed up to SF0, but I figured I'd submit it anyway. It was heavily, and loosely, based on the Fibonacci sequence. It is made up of 100 panels, each panel is 13 x 21 cm, (both fibo numbers). The brush strokes were applied changing direction for each fibo number, ie: 1 one way, 1 another way, 2 aonther way, 3 etc...the darker panels were made using very thin, transparent layers of oil paint. The layers were also applied in a similar fashion. I covered the whole panel in one layer, then the whole panel again, then half the panel, then one third the panel, etc. It was a fun project.