binary (10010110) but only four in the Mangarevan system (VTPK, where V (varu) means 80, T (tataua) is 40, P (paua) is 20, and K (takau) is 10). As binary counting is unknown in other Polynesian societies, it most likely developed after Mangareva was settled (which was sometime between 1060 and 1360 AD). Since Gottfried Leibniz would not invent the modern binary number system until 1689, the Mangarevan binary steps prefigured the European invention of binary by as many as 300 to 600 years. In 2020, Mangarevan binary counting was shown to be an extension of a traditional Polynesian method of counting. Polynesian societies are known to count specific types of objects differently, and they count objects both singly (one by one) and collectively (by twos, fours, or eights). In each case, counting remains decimal (one, two, three...), though the unit counted varies (one, two, four, or eight). In Mangareva, counting collective items decimally produced productive terms for ten (takau or ten singles), twenty (paua or ten pairs), forty (tataua or ten groups of four), and eighty (varu or ten groups of eight). Given the availability of these terms and their associated numerical values, binary counting was then a simple adaptation of traditional Polynesian counting, which set aside every tenth item to mark ten of the items being counted (in New Zealand, this method was misunderstood by Europeans as undecimal or base-11 counting). In the traditional method, the pile of set-asides would then be counted the same way, with every tenth item marking a hundred (second round), thousand (third round), ten thousand items (fourth round), and so on. In Mangarevan binary, in the first round items were counted as before, but in the second round and thereafter they were grouped into eights (varu) and then fours (tataua), twos (paua), and singles (takau). Once counting had shifted to binary units in the second and subsequent rounds, the method was no longer decimal, suggesting an explanation for the upper limit of 800 (for items counted singly) observed for the counting system. Mythology Mangarevan mythology includes deities and gods commonly found across the Polynesian triangle. For instance, traditionally, in Mangareva, the most important god was named Tu, whereas in New Zealand and Hawai'i, the god of war was similarly named Kū. Other commonalities amongst the islands of the Polynesian triangle include the goddess Haumea, who is said to have been responsible for the