Craeted as part of a reserach paper developed for Bridges 08 is about Doyle spiral circle packing. This graphic arose from workng on the paper, though only in that circles are drawn with their centres on two spirals. The sense of depth depends on the order in which the cicles are drawn in each spiral. The only other differences between the two halves of the graphic are the arbitrary colouring of the circles and obvious mirroring. Their spacing ensures that the spirals meet neatly.

http://www.bridgesmathart.org/art-exhibits/bridges2008/sutcliffeA.html