Filler — Rules

Obstacles and walls

A 15×15 board, 7 colours, but part of it is closed:

• Obstacles — about a tenth of the cells. They are not cells at all: they cannot be taken and do not count in the score.
• Walls — barriers between neighbouring cells. A colour does not pass through a wall: cells on its two sides are not neighbours.

The board is new every time but symmetric: turned by 180° it matches itself up to a swap of colours, so the starting positions are equal. Obstacles and walls make corridors and narrow passages — they are easy to block and to cut off the regions behind them. A region walled in and reachable by nobody does not count at all.

To win you need more than half of the cells that remain in play; the number is shown above the board. The variant is unrated. All rules are in the basics.