A nonuniform rational B-spline curve defined by

where is the order, are the B-spline basis functions, are control points, and the weight of is the last ordinate of the homogeneous point . These curves are closed under perspective transformations and can represent conic sections exactly.

More things to try:

Weisstein, Eric W. "NURBS Curve." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/NURBSCurve.html