Alex Y
Sorry I missed your obfuscation of the answer. I almost missed Ed's as well, but two bits equals a quarter, and the overlap is 1/4 of the 4x4 square,

The easy way to see this one is to rotate the 5x5 around the center of the 4x4 by 90, 180, and 270. Each of these three squares will cover a portion of the 4x4 that exactly matches the original, and together they cover the whole 4x4.