Burial
It is thought that this was a building for the preparation of bodies for burial. Note the "XX" figures in the frieze. No, the Mayas did not invent Dos Equis beer. The cross, regardless of orientation, was representative of the four cardinal directions, and the diamond formed by the intersecting X's represented the earth.
Even the places used to hold the body before burial were cross-shaped (see below), and early Spanish explorers misinterpreted the symbolism of the cross, believing that the Maya had had previous contact with a culture of Christian faith, though they had not. 
