Quadrants

Goal

The 6 × 6 board is made of four 3 × 3 quadrants that can rotate. The first player to line up five marbles of their colour, horizontally, vertically or diagonally, wins.

How a turn works

• Place a marble on any empty square on the board.
• Then rotate one quadrant of your choice a quarter turn, clockwise or anticlockwise, using the arrows around the board. The rotation is compulsory, even for an empty quadrant.
• If your marble already makes five in a row before the rotation, you win without rotating.
• If the rotation lines up five marbles for both players at the same time, the game is a draw; if it lines up only the opponent’s, they win.
• If all 36 squares are filled with no line, the game is a draw.

About the AI

Each turn offers up to 288 moves (36 squares × 8 rotations). The engine represents the board with bitfields, applies rotations using precomputed tables and eliminates equivalent rotations. It then explores moves with alpha-beta pruning, a transposition table and iterative deepening, detecting immediate wins by placement or by rotation at every leaf.

At Master level, the AI also calculates as far as time allows (about three seconds per move); the lower levels search less deeply and sometimes make inaccuracies.