Note that on the Mayan Calendar a "zero point" may exists between days 13 and day 1 every 13 days. And that is why I reason THE MAYA ONLY USED THE DAY-SIGNS for THESE TWO DAYS every 13 days, so to identify when a "ZERO POINT" DOORWAY "OPENS".
Vortex energy-flow field "donut" diagram, image edited for educational use.
The very center of the vortex doughnut is the 13/1 transition point that rises up, curls out and down to the outside of the donut path to 7, then curls down then back up thru the center to the 13/1 transition point.
This explains how the energy-field "reverses" as the path transits from and into the center area.
The Mayan calendar "breathes" an in breath & out breath, and "holding" the breathe out on the "outer" weeks.