Back when the original iPhone came out, we worked with some friends of ours in Silicon Valley to dissect the processor. The equipment we used wasn't nearly as cutting-edge as what Chipworks has, but it got the job done.
This is a silicon wafer. Each small square is a chip, called a die. The processor die in the A4 is 7.3 mm on each side, for a 53 square mm total area. The percent of working dies that you can get from a wafer like this is called the yield.
The A4 is actually much more than just a processor— it's a Package on Package, or PoP. In fact, there are three silicon dies inside the A4!