This is a drawing of one of the four bit chunks. The different colors represent either conductive metal traces or different doping of the silicon to get the charge to move in the desired fashion.
The whole thing (all four bits) ends up looking like this. I think it's pretty cool. It helps to understand the math beneath it though to really appreciate its beauty.
Pardon my analism, but let me amend that to
"this is a schematic of a 4-bit adder which can add two numbers, 0-15, plus a carry, and produce a result from 0-31."