Polygonal Structure Excavated

View of the interior of the "Polygonal Structure" after the center of it was excavated.   Notice especially the unusual 12-sided flat base in the center of the structure.

The interior of this structure has 12(!) sides!  In this image several of them are visible as are the "doors" that lead into trapezoidal side rooms.   Note on the floor, below each of the corners are some unusually shaped bases for columns.