The Fool: moves only when attacked (by either army), always after your move.
It flees to squares no one attacks; with none, it kills the cheapest undefended
piece — knights before bishops. It cannot be captured, blocks everyone, and
gives real check. Pieces currently menacing it are outlined in dashed red. You pick when it has equal choices. Fool-mate is a draw; a Fool
forced to check its own patron ends the game drawn.