It was just a way to keep the eggs from rolling around the baking sheet, while containing the color. But, when I set my newly dyed green Easter Egg onto a paper towel, I accidentally started the process of chromatography.
For chromatography, you need two things:
1) fibers, such as in a paper towel or coffee filter, to transmit the liquid
2) moving liquid, such as water, which dissolves the dyes and carries them through the paper.
Apparently, the water running down off of the egg and soaking the paper towel was enough to push the dyes further away from the egg, and start the colors separating.
Notice the ring of beautiful blue around the green dye. There are also spots of yellow in the middle of the green, which at first I thought must have dripped from a yellow egg, but turn out to be the yellow dye remaining after the blue dye is separated out. (I repeated the experiment, keeping yellow eggs far away, just to make sure.)
I also noticed this effect with blue, which separated slightly so that one patch of blue was a little darker violet, but it didn't photograph well.