Arizona State University professor Dr Sherry Towers spent several years studying the Sun Temple archaeological site at Mesa Verde National Park in southwestern Colorado, an important regional ceremonial centre for the ancestral Pueblo peoples, constructed around 1200 CE.
     Dr Towers explains: "I noticed in my site survey that the same measurements kept popping up over and over again. When I saw that the layout of the site's key features also involved many geometrical shapes, I decided to take a closer look."
     The shapes were familiar: equilateral triangles, squares, 45-degree right triangles, Pythagorean triangles, and the "Golden rectangle" known to architects in ancient Greece and Egypt. All are fairly easy to construct with a straight-edge, a compass or cord, a unit of measure and some knowledge of geometry. However, unlike the ancient Greeks, Egyptians, and Maya, the ancestral Pueblo people had no written language or number system, and yet their measurements were still near-perfect, with a relative error of less than one percent.
     Dr Towers says: "The genius of the site's architects cannot be underestimated. If you asked someone today to try to reconstruct this site and achieve the same precision that they had using just a stick and a piece of cord, it's highly unlikely they'd be able to do it, especially if they couldn't write anything down as they were working."
     Dr Towers revealed that the site was laid out using a common unit of measurement just over 30 centimetres in length, as well as evidence that some of the same geometrical constructs from the Sun Temple were used in at least one other ancestral Puebloan ceremonial site - Pueblo Bonito, in New Mexico's Chaco Canyon.
     "Further study is needed to see if that site also has the same common unit of measurement," Dr Towers adds. "It's a task that will keep us busy for some years to come."

Edited from Phys.org (23 January 2017)