Patterns

Prickly pear skeleton, photo by Carol Tornow

Smiling prickly pear, photo by Angie Perryman

Patterns in nature are studied by U of A Mathematics Professor Alan Newell, who is quoted here: "All the lovely patterns on plants have their origins in mechanical forces and biochemical processes." (Thanks to Patricia for the link.) Wish I could write that the pattern on the prickly pear is simply optimally-placed cochineal! Alas, this smile is the work of some human animal. (Maybe they got a spine or two for their trouble. Those do grow in a pattern.)