Fenced In
 
 
 The farmer asked each of his sons to fence in two sections of land. To the first son he said, "Go and fence in the land over there that is half a square mile." To the second son he said, "Go and build a fence around the land over there that is a half-mile square." Each son did exactly as he was told, but the farmer couldn't believe that each son had a different result.

Which son fenced in the larger area?
 

Answer: