 He suggested that the glyphs might have been made in the 1920s by Australian soldiers who had served in Egypt, citing an example of shapes in the form of the Sphinx and a pyramid known to have been made by a returning soldier.Australian Professor of Egyptology Naguib Kanawati has also stated that they are not authentic, saying that the hieroglyphs within the same panels were of widely different periods and some were carved backwards.Geologists have stated that the sandstone in which the hieroglyphs are carved erodes quickly and nearby 250-year-old Aborigine petroglyphs show considerably more erosion.