The Sacred Calendar of the Mayans is activated by combining the numbers 1 - 13 with 20 day signs. As explained in the book "Day Signs" by Bruce Scofield, sequences derived from these combinations have a cycle of 260 days.
There are also the cycles of 13 in this calendar. Each of the 20 named days being prominent once in the total cycle. This prominent day, says Scofield, influences the following days. For example, you could be a Deer born under the influence of the the 13 day cycle beginning with 1-Earthquake. Your specific day sign would then be "11 Deer".
These computer drawings are based on designs from examples of existing Mayan writing from several different sources. One of the most interesting books is "Breaking the Maya Code" by Michael D. Coe. The book describes the series of breakthroughs that finally led to being able to "read" the Mayan inscriptions.