It’s also useful to remember that the pieces can be
meshed at various angles of rotation. Since there are
16 teeth on the side of the half bush, each tooth corresponds
to 22.5 degrees; this is the minimum value by which we
can change the angle of two meshed pieces. This arrangement creates some useful possibilities. For example, you can use two half bushes to couple two switches in such a
way that turning one switch on turns the other one off (see
Figure 4-10).