A perpetual calendar is a calendar valid for many years, usually designed to look up the day of the week for a given date in the past or future.
Illustration from 1881 U.S. Patent 248872, for a perpetual calendar paperweight. The upper section is rotated to reveal one of seven lists of years (splitting leap years) for which the seven calendars below apply.
A 50-year "pocket calendar" that is adjusted by turning the dial to place the name of the month under the current year. One can then deduce the day of the week or the date.
Breguet classique Grand complication perpetual calendar
Perpetual calendar wristwatch by Patek Philippe
A watch is a portable timepiece intended to be carried or worn by a person. It is designed to keep a consistent movement despite the motions caused by the person's activities. A wristwatch is designed to be worn around the wrist, attached by a watch strap or other type of bracelet, including metal bands, leather straps, or any other kind of bracelet. A pocket watch is designed for a person to carry in a pocket, often attached to a chain.
A modern wristwatch featuring solar charging and Bluetooth capabilities
A 1983 Casio watch with touchscreen
A pomander watch from 1530, which once belonged to Philip Melanchthon and is now in the Walters Art Museum, Baltimore
A watch drawn in Acta Eruditorum, 1737
