The 260 Count
Let us consider the 5-segment configuration first, as it represents the older calendar reckoning of the 260-day count. We have inactivated the uppermost segment of the 8-segment circle formed by the ring of towers on the Aztec Calendar, and thereby divided the remaining segments into five equal 63-degree segments. The spatial division that results may be observed in the following configuration:

This 5-segment configuration may represent the 260c reckoning on the calendar (ignoring for now the calendar's rings and their respective elements).

Each of the five segments represents 52 days, or four 13-day cycles (trecenas). Now, let us observe the lines that might correspond to the spatial subdivisions equivalent to the 13-day cycles within the 260c.

Now let us examine these different configurations of the 5-segment divisions with respect to the lines on the calendar's concentric rings. We shall transpose the abstracted lines of the spatial divisions onto the face of the Aztec Calendar in order to see whether a relationship exists between the two sets of lines.

Observe the close correspondence between the two sets of lines. In this case, the abstracted lines seem to coincide almost exactly with the divisional lines on the ring of serpents.

The above illustrations may suggest that a spatial division along these lines of configuration might have served as a basis for designing the ring of serpents within the Aztec Calendar. Curiously enough, there is an image that might suggest that the 5-segment configuration of space shown here was employed in the abstracted division within the calendar's design.

The opening on the circle's circumference also reminds us of other open-ended designs found in many distinct cultures. The first example that comes to mind is the floorplan design of Stonehenge in Great Britain.

We might also consider the similitude in design of some ancient pottery vessels.

Equally intriguing is the pottery of North American indigenous peoples who painted an open-ended circle on their bowls and plates:

The open-ended configuration also resembles the shape surrounding the claws of the Nahui Ollin within the Aztec Calendar:

The list of similar images is far too extensive to cite here, for the configuration is not foreign to ancient cultures, as one might have initially conceived.