Historic chroniclers described counting devices used by accountants that look like the carved devices. The name of these devices "yupana" literally derives from

Historic chroniclers described counting devices used by accountants that look like the carved devices. The name of these devices "yupana" literally derives from the verb "to count". They all preserve some kind of 5-3-2-1 relationship that's related to the usage. What's shown would make for very strange terraces. Most Andean terraces run perpendicular to the vertical face. Saddlepoints are much less common, probably because they're small, usually at the wrong altitude, have lots of erosion, and the air dynamics are really weird.