End the Stalemate

At the beginning of your end step, if no creatures attacked this turn, put a white counter on End the Stalemate.
At the beginning of each opponent's end step, if no creatures attacked this turn, put a black counter on End the Stalemate.
At the beginning of each upkeep, if there are three or more of each white counters and black counters on End the Stalemate, you win the game.