The assignment said to do a mathematical composition, so initially I thought of the Golden Ratio which we'd discussed in class earlier. That lead to me to this sketch which I manipulated for my assignment: http://www.openprocessing.org/sketch/10274. I wanted to play with the light source created by the gradient background, so I created a staircase effect and wanted to get the color to go through each set of steps after a delay (this didn't work and I realized that I should probably have used pushMatrix() and popMatrix() maybe but I'm not too clear on how those work). What was interesting to me was the hue because depending on the hue you were at, the light source of the piece changed.
So if I ever need to test which greys to use with what colors, I might actually use this to figure out contrast.