Fieldmark Mahjong Mat - OctagonExcluded from all discounts PRE ORDER. Estimated delivery 6 26. The Octagon Mahjong Playing Mat is a new shapedesigned by Haus of Tiles to bring balance and intention to the table. Our signature octagon design is patent pending. Where square mats can extend past the edges of a round table, the octagon fits cleanly and precisely. It works perfectly on a 36" round table, while also scaling beautifully on larger round, square, and rectangular tables.