Telecles and Theodoros, the sons of Rhoecos, who were the most renowned of the ancient sculptors, are also reputed to have spent time with the Egyptians. [Beyond inserting this information which can be dismissed at the level of rumour, Diodorus goes on to supply precious information of practice which certainly authenticates his claim.] They carved the wooden statue of Pythian Apollo for the Samians, of which it is reported that half of the image was fabricated by Telecles in Samos, and the other half was completed by his brother Theodoros at Ephesus [...] Now this way of working is never practiced by the Greeks, but it is the rule of the Egyptians, for among them the proportions of the statues are not determined by the appearance of the eye, as among the Greeks, rather [...] they determine all the relative proportions, from the smallest to the largest, by dividing the scale of the complete body into twenty-one and a quarter units, whereby they derive the entire symmetry of the image (Davis, 1979; emphasis added).  
It is important to comment in passing that the accuracy of many writers of antiquity has been doubted by modern scholars for a variety of reasons, which are probably underpinned by considerations of 'race'. Moret (1927, p. 432), for example, dismissed Diodorus' eyewitness account as exaggerated. But the period of relevance for Greek art was the period of its cultural contact with Kmt from the eighth century BCE, when Greeks were used as mercenaries in the State army and when they were also involved in trade, although confined to one particular location, Naukratis. Over successive epochs, the grid system for determining proportions varied: in the Old Kingdom it consisted of 18 squares