This photo features a bow balanced on the strings of a viola, amidst a pile of music. It was contrived by finding the center of mass of the bow, and making this the balance point where it rests on the strings. The bow does not have a uniform density, so the center of mass of the bow is not simply located halfway along the length. Instead, trial and error was used to determine where the bow could rest that would allow it to remain on top of the viola without tipping. The end of the bow that is nearest to the camera in the picture contains more mass than the far end, so its distance from the center of mass is smaller. The strings of the viola support the bow at its center of gravity, which is the average location of the force of gravity on the bow, and at the same point as the center of mass.