Panel 1:
Xeno and Estragon, on opposite sides of a chess board.
Estragon: Checkmate.
Xeno: No, that's only check. Look, I can move my queen here. Now I'm not in check.

Panel 2:
Xeno and Estragon.
Estragon: Checkmate.
Xeno: You moved a pawn into a weak position. I'm taking it with my rook. That's not checkmate.

Panel 3:
Xeno and Estragon
Estragon: Bingo.
Xeno: You suck at chess.