More comments on organiztion of the Plates.

I have perused many of the plates in an attempt to understand the complex arrangements of icons and more complex paintings. The number 13, or number of lunar cycles per solar year is an intimate part of the tonalpohualli illustrated in figures 1 thrigh 8..

I decided to think of the bottom row of squares in figures 1 thru 8 as being a matrix used to hold a stone marker which is advanced one square to the left at the time of a new moon. This requires the stone to be moved to the second row, the next line of rows above, after four years. How can the extra day be added to account for the extra time required to maintain a count of coordinated agricultural, solar, cycles?

I will answeer this question when it becomes apparent to me. I assume that there have been hundreds of years of stellar observations before this codex was recorded. This is evident because of the diligent organization which must have required a long recorded count of moons, solar cycles, and probably stellar cycles.