Roulette (curve) in this case, the point lies on the circle then the roulette is a cycloid. A related concept is a glissette, the curve described by a point attached to a given curve as it slides along two (or more) given curves. Formally speaking, the curves must be differentiable curves in the Euclidean plane. The "fixed curve" is kept invariant; the "rolling curve" is subjected to a continuous congruence transformation such that at all times the curves are tangent at a point of contact that moves with the same speed when taken along either curve (another way to express this constraint
Rolling stock of the South Manchuria Railway number, which followed the type indicator letter. This class designator was then followed by the road number, counted starting at 1. As in Period 2, the American-style wheel arrangement was used as the basis for the classification system introduced in 1920. However, in the new system, the American name was used as the basis for the class name, using two syllables of the American name as the new class name. The class name was made up of three katakana, of which the first two indicated the wheel arrangement, and the third indicated the class number – i.e. first, second, third,