The enclosures of this phase are smaller in plan and use smaller pillars than the Layer III enclosures.

Some of the Layer II structures are rectangular rather than oval.

The animal imagery and rich carved decoration of the earlier phase is reduced or absent in the later structures.

The overall impression is of a simpler, less ambitious program of construction.

What accounts for this change?

Several possibilities have been proposed.

One is demographic or social: the communities using the site may have changed in composition, with different groups now dominant or with the social networks that had enabled the Layer III construction altered.

Another is practical: the sustained labor required to build and maintain the large Layer III enclosures may not have been sustainable indefinitely, and the Layer II construction may reflect a scaled-down version of the earlier tradition adapted to the available labor and social resources.