Blancpain made a big splash in 2004 with their new Equation du Temps Marchante watch. It was the first time this complicated feature, previously only seen in large clocks and pocket watches, was brought to a wristwatch. The watchmakers had to get creative and design a unique gear train and differential to make it all work. The watch also has a plus/minus scale equation display, along with a retrograde moon phase and perpetual calendar. The movement is beautifully decorated with hand-carved bridges and a winding rotor featuring an artist's depiction of the sun. The reference 6638-3431-55B model has a platinum case and a white grand feu enamel dial.