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 on 6 January 2017, as the lead single from their 25th live album, "Let There Be Light" (2016). "What a Beautiful Name" was composed in December 2015 in Sydney, Australia, for the upcoming Hillsong Conference, the annual church gathering. The scriptural foundation of the song can be found in , and . According to sheet music published at Sheetmusicdirect.com by Hillsong Publishing, "What a Beautiful Name" is a slow tempo of 68 beats per minute. Written in common time, the song is in the key of D major. Brooke Ligertwood's vocal range spans from A to B during the song.