"Some are as big as cupcakes, others are the size of a penny. They... come in a range of colors as varied as drugstore lipsticks."

From a review of "Playboy: The Complete Centerfolds," that's a description of nipples, photographed in the years 1953 through 2007. Evolution is slow, but when you can choose your models, nipples adapt quickly to whimsical tastes. Other parts are easily reconfigured:

Pubic hair diminishes as the nineties draw to a close. Neat triangles turn to Band Aid-sized strips, which become little Hitler mustaches or nothing at all. The modern crotch is a bit prim, a bit less forthright. You'd think that depilation would lend a youthful look to the genitals but it has the opposite effect instead, making the girls look older and slightly jaded. (Intimate grooming signals forethought.) The youthful quality of the early centerfolds disappears.

The review is written by a woman — couldn't you tell? — Molly Young.