A polygon tile for tessellating includes a body, a cross-member attached to the body, and a sheet extending tautly over the body and the cross-member. The body includes an upper surface, a lower surface, and a perimeter wall defining a first corner, a second corner, and a third corner. The cross-member extends from the first corner to the third corner and includes a first end, a second end, a middle portion, a bottom end attached to the upper surface, and a top end tapering to an apex. The cross-member tapers in height from the middle portion to the first and second ends forming a bowed curvilinear shape. The first and second ends are substantially coextensive with the body. The sheet extends tautly over the perimeter wall and is attached to the lower surface of the body. The sheet slopes from the middle portion to the perimeter wall in all directions.