This is the East Palace in the Quadrangle of the Nuns, and the southwest corner. Door #5 (depending on from where you start counting) features, above it, a frieze of trapezoids consisting of parallel bars. At the end of each of these, the design features serpents' heads. Their background consists in the usual latticework. At the corner, there is a stack of 3 Chaac masks, but on this occasion, and quite uniquely, the protusion or nose rises upward and curls, rather than downward. Construction dates from between 900 - 1000 CE.
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