On a rectangular base stand three figures assembled from bolts, wood and metal: two rotating propellers (two children) intent on their game and the central tower (Mother Superior), whom with her long arms illuminates and protects with impartiality the many revolutions. The three characters interact with the aid of a transmission belt, which attached to a small electric motor will produce a circular motion. But the careful observer will notice that an extension of the prioress illuminates with greater emphasis one of the two propellers, thus one of the two kids runs more quickly than the other. It can't be helped when one becomes two: "There must always be a preference."