Visiting the Musée international d'horlogerie in La Chaux-de-Fonds, I fell in love with a fan-shaped pocket watch with a double ( hours & minutes ) retrograde complication (sometimes called 'sector' complication, apparently). The idea of Vacheron Constant...
Took us two visits to absorb the wonders within. Your focus on double retrogrades also brought to mind the bras en l’air. I recall V&C’s first was in 1930 but there were others who offered this complication in the 19th century. Christies photo ...