Chess variant on an infinity-symbol shaped board; as if we had bent a 18x4 sized strip and glued to its two sides.
Otherwise the rules of chess apply, with the following differences:
The rook and the queen is way more valueable than the other pieces, because these pieces can move along a very long path, morover if they stand in the middle of the board, they are able to control two parallel paths. The bishop is much less valueable as the diagonals are often short on this board. See also: Value of pieces.