How does a perpetual calendar work?

A perpetual calendar is designed to accurately track the date across multiple years, accounting for leap years and varying month lengths. It uses a combination of gears and mechanisms to calculate days, months, and years, adjusting for the irregularities in the Gregorian calendar. By incorporating leap years every four years, except for years divisible by 100 but not by 400, it ensures precise date representation over long periods. This allows it to display the correct date without needing manual adjustments.