We solve Conway's Angel Problem by showing that the Angel of power 2 has a winning strategy.
An old observation of Conway is that we may suppose without loss of generality that the Angel never jumps to a square where he could have already landed at a previous time. We turn this observation around and prove that we may suppose without loss of generality that the Devil never eats a square where the Angel could have already jumped. Then we give a simple winning strategy for the Angel.
(Received August 02 2006)
(Revised October 18 2006)
† Partially supported by the Hungarian Scientific Research Fund grant no. T 49786.