This hieroglyph is the oldest known record of the Maya calendar
The system is still used today, a testament to the persistence of Maya knowledge

These two plaster mural fragments jigsaw together to form a record of the date “7 Deer” from the ancient 260-day Maya calendar. The pieces, which fit in the palm of a human hand, may have accompanied a scene or human figure as a sort of ancient timestamp.
San Bartolo-Xultun Regional Archaeological Project