"The façade is organized so that the three entranceways divide the wall space into four equal sections. Above the doorways, the frieze is bordered by upper and lower projecting cornices. Situated over each doorway is a niche 1.67 m hight, 0.96 m wide. and 0.43 m deep. On the back wall of the niche are three roughtly square mortises of about 12 cm dimensions. they are arranged in a vertical line and were used for tenoning stone and stucco sculpture. Immediately below each nich is a zoomorphic mask panel which served as a throne for the seated stucco figure once inside each niche. One niche of similar proportions appears on each end of the structure and three on the rear façade."
Carolyn E. Tate, Yaxchilan: The Design of a Maya Ceremonial City, p. 188