Thomas de Colmar is best known for his sophisticated mechanism designed to realize all four arithmetic operations, which was first mass-marketed in machines called Arithmomètre. Part of Thomas' marketing strategy was the production of a series of prestige pieces in the form of particularly splendidly designed Arithmomètres, which were gifted to influential personalities of his time. One of these prestigious objects was the large Piano Arithmomètre, which Charles Xavier Thomas made for the 1855 Universal Exhibition in Paris. The Piano Arithmomètre is visualized and explained in detail in this 3D animation. The video was made by Felix Nöhre as part of his master's thesis and in collaboration with the Arithmeum, and highlights the piano arithmometre as a special showpiece.