The interlocking Tzolk'in and Ha'b wheels of the Maya calendar.
The Mayan Calendar Round meshes two independent cycles: the 260-day Tzolkin (a sacred count of 13 numbers and 20 day-signs) and the 365-day Haab (the solar year). Like two gears of different teeth, they realign only once every fifty-two years — a complete "round."
This unlocks a sophisticated model of interlocking time: sacred and civil counts running in parallel, each naming a day, together producing a unique signature for every date. It demonstrates, independently of the Old World, the same deep insight — that combining modest cycles yields vast, non-repeating order, and that time can be counted in more than one base at once.