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
What a Beautiful Name to sing and which does not strain the voice with notes that are too high or too low. He also comments that the song is written in the key of D which is "the optimal key for both men and women." "What a Beautiful Name" had its worldwide digital release on 6 January 2017, and topped Billboard's Hot Christian Songs chart on 25 February. The single has held the top position for 38 weeks making it the second-longest-leading No. 1 in the 14-year history of the Hot Christian chart. The song which claims the distinction as the longest-leading No. 1