"Structure III, a low linear mound at the east side of the plaza, was so designated by the Carnegie Institution expedition. It is a featureless mound, probably a low structure with a series of rooms opening onto the plaza. Nothing is known about its decoration, and least of all, its roof comb, if any; but in terms of mass, it is certainly the weakest structure of the four that enclose the plaza.
Its very weakness, however, and the relatively wide spaces between it and the adjacent structures may have provided aesthetic relief from the massiveness and tight spacing of the other three structures. It is interestiing but perhaps futile to consider whether this was deliberate on the part of the Maya architects.
Did they in fact value this kind of visual variety, or did social collapse simply catch up with them before they got around to building the next and larger structure in place of what we now know at Str. III? Given the impressive results of some of their plaza spaces, it seems reasonable to think this subtlety was deliberate."
(Potter, p. 8)