Flatness measurement is usually performed by measuring straightness of multiple lines along the flat surface. These types of holes require special equipment to maintain the straightness and tolerances. Once ready, the artisans examine the smoothness and straightness and measure the dried hollow tube. Camber refers to the "straightness" of the tube. This has similar benefits as riding down the centerline, as it tests for straightness. Another common inspection point is the straightness of a bolt or screw. During the process, a cable's torsion and straightness are monitored. It also is selected because of its straightness, and well-spaced nodes. Butterworth postulates that it may be Roman (from naming evidence and its straightness). Importantly the straightness of his arm was never contradicted by umpires. For all the straightness of her back, she walked with a slouch. More importantly, it is a good training tool to test the horse's straightness. It was so named because of the straightness of the Air-line railroad route. When working on straightness in the horse, a common exercise is used called 'shoulder in'.