Mesoamerican (Mayan, others) 260 day calendar cycle, shown as interlacing moving faces agaist a steady hand.
http://diskclock.com/
http://diskclock.com/
http://diskclock.com/
http://diskclock.com/
http://diskclock.com/
http://diskclock.com/
http://diskclock.com/
http://diskclock.com/
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