When the rotation of the window is observed, the window appears to rotate through less than 180 degrees, though the exact amount of travel that is perceived varies with the dimensions of the trapezoid. It seems that the rotation stops momentarily and reverses its direction.
The observation of a rotating window reveals that it moves through an angle less than 180 degrees, and the perceived amount of movement is influenced by the dimensions of the trapezoid. This rotation stops momentarily and then reverses its direction.