Both part of Cartier's watchmaking heritage, the "mysterious display" and "day/night indication" complications appeared the same year, in 1912 when Cartier presented two clocks: the Model A which debuted the mysterious movement, and the Comet (or Planet) Clock for the day/night movement. This is the first time that Cartier has brought both these complications together in a wristwatch. Positioned at the top of the Rotonde's wide dial, a sapphire disc continually rotates, revealing first the sun then the moon. They take turns to sweep the hour scale over a 180° segment. Minutes are shown underneath, by a retrograde hand. This timepiece is also available in white gold.