Many theories for the skill of Tiwanaku's architectural construction have been proposed. One is that they used a "luk’ a," which is a standard measurement of about sixty centimeters. Another argument is for the Pythagorean Ratio. This idea calls for right triangles at a ratio of five to four to three used in the gateways to measure all parts. Lastly, Protzen and Nair argue that Tiwanaku had a system set for individual elements dependent on context and composition. This is shown in the construction of similar gateways ranging from diminutive to monumental size, proving that scaling factors did not affect proportion. With each added element, the individual pieces were shifted to fit together.