Back by popular demand, the SMF Arcade!!! PLAY NOW!!!!!!!!!!!!!!!!!!!!!!!!
I've mentioned it before in a different thread but I've had free castle games with TONS of dead spots and defiantly were not caused by walls.
If you can't replicate the dead square phenomenon, it's doubtful you fully understand it. Would it be possible tofarm in an entire expansion like 4 with dead squares??? =O