At the heart of the QP à Équation lies Greubel Forsey’s seventh invention, the Mechanical Computer, an entirely integrated 25-part component that brings a totally new interpretation to some of the calendar functions incorporated in age-old astronomical clocks. It is composed of a set of coding wheels superimposed in a coaxial manner, along with removable fingers programmed by this ingenious system. The dial of the QP à Équation indicates leap years, the 24 hours of the day and night, the day of the week, the large date, the month, the hours, the minutes and the seconds, ...as well as the chronometric 72-hour power reserve. On the movement side, this timepiece displays the equation of time with the months, seasons, solstices and equinoxes, as well as the calendar year. The QP à Équation provides a simplified linear display. Herein lies the happy paradox of this piece: it is an ultra-complicated timepiece with its tourbillon and its complete equation of time perpetual calendar function, but it is as easy to use and adjust as a watch with three hands. This system is extremely easy to adjust in both directions without damaging the mechanism.