Description

Petrify is a finite territory game for two players: Blue and Orange. It is played on the spaces (squares) of an initially empty square grid (board). The recommended board sizes are between 6x6 and 10x10 squares.

Both players must have access to a sufficient number of disks of their own color and a sufficient number of neutral blocks.

A group is a disk along with all other like-colored disks one could reach from it through a series of steps between orthogonally adjacent disks of its color.

Similarly, a patch is a square not occupied by a block along with all other such squares one could reach from it through a series of steps between orthogonally adjacent squares not occupied by blocks. Note a patch may contain any number of groups, as well as empty squares.

The size of a group or patch is the number of squares it spans.

A mound is a set of four blocks occupying a 2x2 area of the board.

A barricade is a set of three adjoining blocks in a straight diagonal line.

Mounds and barricades are illegal formations. For the purpose of spotting them, the edges of the board count as lines of blocks. In other words, the real board is considered to be the middle section of an imaginary board with sides two squares longer, and all edge squares on this larger board are considered to be occupied by blocks.

Blue plays first, then turns alternate. On your turn, if possible, make exactly one of these board plays:

• Place a disk of your color on an empty square.

• Move a disk of your color any number of squares in a straight orthogonal or diagonal line, without jumping over any blocks or enemy disks, to a square occupied by an enemy disk. Then, remove this enemy disk and place a block on the square from which you just moved your disk, without forming a mound or a barricade. Note a disk can jump over friendly disks.

If you have no board plays available on your turn, you must pass. Passing is otherwise not allowed.

The game ends when both players pass in succession. Then, for each patch on the board, the players jointly remove pairs of opposite-colored groups of the same size from it until there are no more such pairs to remove. The player with the biggest group left over in a patch owns the patch. Empty patches are owned by neither player.

The player with the higher score in the resulting position wins. Your score is the sum of the sizes of the patches that you own. If there is a tie, whoever made the last board play loses.

The pie rule is used in order to make the game fair. This means Orange will have the option, on their first turn only, to swap sides with Blue instead of making a regular move.