Recreational mathematics Mathematical games Angel problem Hex (board game) Shannon switching game Phutball Hackenbush Graph pebbling Sim (Pencil Game) Sprouts (game) Winning Ways for your Mathematical Plays Map-coloring games Dawson's Chess Grundy's game Sprague–Grundy theorem Impartial game Nim [[1]] Combinatorial game theory Fuzzy game Nim-sequence Nimbers Dr. NIM