Computers change a lightbulb

Question: How many chess computers does it take to change a lightbulb?

Answer: Four. One to remove the lightbulb by capturing it en passant, one to put the new one in by taking back the move whereby the old one was unscrewed, one to go snatching some pawns while all this action takes place on the other side of the board, and one to flash its lights, make lots of noise, and announce out of the blue that it has found a forced mate in seven.