The Courtyard of the Pillars is one of the few spaces at Teotihuacan where architecture and sculpture are experienced together. Each pillar reveals a quetzal head seen in profile and butterfly wings arranged frontally—except for the pillars on the west side, where two profiles combine to form what appears to be a nocturnal bird, possibly an owl. As you move around them, the figure shifts with each step. This appears to be a deliberate effect, unusual in Mesoamerican sculpture, that turns the visitor's movement into part of the experience of the image. The quetzal and the butterfly are not an arbitrary pairing—together they may represent transformation as a sacred principle.