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Perpetual Calendar

A calendar mechanism that automatically adjusts for the unequal lengths of all 12 months, including leap-year Februarys (compare with “annual calendar”). Nearly all perpetual calendars will maintain the date until February 28, 2100 when, due to a quirk in the Gregorian calendar that says 2100 will not be a leap year despite being divisible by four, these calendars will need to be reset.

Perpetual Calendar

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