The numerals are made up of three symbols: zero (a shell),[1] one (a dot) and five (a bar).
Other than the bar and dot notation, Maya numerals were sometimes illustrated by face type glyphs or pictures.
There are different representations of zero in the Dresden Codex, as can be seen at page 43b (which is concerned with the synodic cycle of Mars).
[3] It has been suggested that these pointed, oblong "bread" representations are calligraphic variants of the PET logogram, approximately meaning "circular" or "rounded", and perhaps the basis of a derived noun meaning "totality" or "grouping", such that the representations may be an appropriate marker for a number position which has reached its totality.
(The Maya had however a quite accurate estimation of 365.2422 days for the solar year at least since the early Classic era.
The earliest long count date (on Stela 2 at Chiappa de Corzo, Chiapas) is from 36 BC.
Indeed, many of the earliest Long Count dates were found within the Olmec heartland.