Click on an arrow to drop a piece. Click the green flag to restart.
Made as an experiment in using recursion in Scratch. Algorithm: iteratively-deepening minimax only pruned at win states. Easy: search depth limited to 4 moves, no heuristic. Medium: search depth limited to 6 moves, no heuristic. Hard: The heuristic used only considers horizontal combinations. Try to outsmart it with diagonals.