US Patent 8051575 Mounted scale bar

A scale-bar artifact can include a base, a structural component, at least two nests disposed on the structural component and configured to receive a spherically shaped object having a center, and at least three mounting assemblies, each mounting assembly including a first portion and a second portion. The second portion of each mounting assembly is coupled to the base. The first portion of each mounting assembly is coupled to the structural component. The first portion and second portion of each mounting assembly are in mutual contact. Each mounting assembly has a center of rotation. The centers of rotation of the three mounting assemblies share a common plane with the centers of the spherically shaped objects.