A distinctive counting method found in New Guinea counts yams by sorting them into groups of thirty-six and then six, setting one aside from each group for the next round of counting. This method of counting-by-sorting is similar to one found in Polynesia. Like the Polynesian variant, New Guinean yam-counting creates an ephemeral abacus, ephemeral because the abacus exists only while the counting is performed, and an abacus because the method represents exponential structure. The exponential structure created by yam-counting reaches an impressive six to the seventh power, or 279,936. Such counting-by-sorting is physically and mentally efficient, minimizing the physical effort of moving items to count them and the mental effort of keeping track of the count. Other distinctive methods found in New Guinea count things by threes (Arapesh), fifteens (Huli), sixteens (Wuvulu), or sixties (Ekari). The Ekari sexagesimal system is the only other one known besides the number system of Mesopotamia. It most likely represents an independent invention, rather than cultural transfer. Iqwaye finger-counting counts to 400 on the fingers and toes of a single person.