Acton is 40 years old. I wonder how much his age had to do with his rejections four years ago? At 36 he certainly would've stood out at Facebook in 2009.
It is an awful question because not all manhole covers are round. There are plenty of rectangular manhole covers, semi-round hinged ones, triangular ones, etc.
Ah I thought it was because the Ninja Turtles like pizza and they live in the sewer and the the easiest way to get a round pizza into the sewer is though a round manhole cover.