You can't move diagonally past a corner. Does moving through a doorway on the battlemat count as a corner? I.e., I can't move diagonally through a doorway?
---------- |A1|A2|A3| |B1|B2|B3| |==|C2|==| |D1|D2|D3|
D1 and B1 have a wall between them and D3 and B3. Could I move diagonally from D1 into C2?