Olmec colossal heads the monuments with ropes. Two heads from San Lorenzo have traces of niches that are characteristic of monumental Olmec thrones and so were definitely reworked from earlier monuments. Seventeen confirmed examples are known. An additional monument, at Takalik Abaj in Guatemala, is a throne that may have been carved from a colossal head. This is the only known example outside of the Olmec heartland on the Gulf Coast of Mexico. Possible fragments of additional colossal heads have been recovered at San Lorenzo and at San Fernando in Tabasco. Crude colossal stone heads are also known in the Southern Maya area
Maya numerals and the Long Count calendar predated the Maya, and was possibly the invention of the Olmec. Indeed, many of the earliest Long Count dates were found within the Olmec heartland. However, the Olmec civilization had come to an end by the 4th century BC, several centuries before the earliest known Long Count dates—which suggests that zero was "not" an Olmec discovery. Mayan numerals were added to the Unicode Standard in June, 2018 with the release of version 11.0. The Unicode block for Mayan Numerals is U+1D2E0–U+1D2FF: Maya numerals The Mayan numeral system was the system to represent numbers and calendar