"Clemency Coggins has shown how the Twin Pyramid Groups at Tikal, built to host katun-ending ceremonies, were representations of the Maya cosmos. As such, these architectural groups simultaneously symbolized the threefold and fourfold aspects of the universe. The pyramids on the east and west represent the earthly plane and mark the cycles of time, specifically the [daily] birth and death of the sun. The nine-doorwayed building on the south represents the nine-layered underworld. And the walled enclosure on the north, open to the sky, represents the celestial domain, a fitting place for the stela and throne stone of the sponsoring ruler to reside."
Robert Sharer, The Ancient Maya, p. 524
NOTE: A katun is a twenty-year ritual period observed by the Maya.