Biarcs and bilens ?
Biarc curves are considered from the standpoints of the theory of spirals and Mbius maps. Parametrization and reference formulae, covering the whole variety of biarcs, are proposed. A region is constructed, enclosing all spirals with common circles of curvature at the endpoints. This region, named bilens, is bounded by two biarcs.
biarc bilens spiral mbius map lens