#216 Game of stones
Set by Daniel Griller
Let’s play a game, dear reader. I have placed three stones on a number line: one on 0, one on 20 and one on 40. You and I shall take the game in turns; on a turn, a player picks up one of the two outer stones and places it on a whole number between the other two stones. The game continues until the stones occupy three consecutive whole numbers, whereupon no further moves can be made, and the game ends. The player who made the final move is the winner.
As …