That redesigns the moonphase wheel – itself a large part of the perpetual calendar aesthetic – with a black and silver design, rather than the blue and gold which is more common.

The challenge of leap year has led to the development of the perpetual calendar - a complication that has been part of the A. Lange & Söhne repertoire since the late 19th century.

Typically, almost all perpetual calendars work with a 48-month wheel, because most watches have the hour, minute, and second positioned at the center of the dial, as Schmid points out.

Glashütte Original Senator Excellence Perpetual Calendar Ref. 1-36-12-03-02-64 | Image: Supplied Senator Excellence Panorama Date Moon Phase Ref. 1-36-24-02-02-64 | Image: Supplied ...

The Endeavor Perpetual Calendar Tutorial and reimagined Funky Blue edition are available now for $65,000 and $60,000, respectively. Each comes with a hand-stitched kudu leather strap.

Unlike any perpetual calendar in existence, the Perpetual 1 used a wheel-based mechanism instead of the usual levers so it could be much more easily set and adjusted.

Hence, the reference 5550P was the first Patek perpetual calendar to use the 240 Q movement, with escape wheel, pallet fork, balance wheel and hairspring all made from silicon.

Perpetual calendars are mechanical masterpieces that correctly display the month, date and day, with some featuring a leap year indicator, without requiring any adjustments at midnight on February 29.

The MB&F Perpetual, its four sub-dials, two mainsprings, 581 parts and entirely reinvented perpetual calendar complication all sit inside a 44mm stainless steel case.