In Christian Hesse's book The Joy of Chess one reads about a mate-in-3 problem composed by Pál Benkö that stumped Bobby Fischer. Hesse gives the following diagram:
[FEN "8/8/8/4k3/8/8/8/2BQKB2 w - - 0 1"]
On the other hand, on ChessBase a slightly different diagram is given:
[FEN "8/8/8/8/4k3/8/8/2BQKB2 w - - 0 1"]
Curiously, both of these positions are valid three-movers with the same key move! But which one is Benkö's actual composition?