|Most basic functionality: Just planar tweening. Also works with more than two curves.
Here, two inner and one outer curve.
|More planar tweening.
|But Tweener tweens on any 3d surface, between any, not necessarily closed curves!
Here, tweening on a surface between its two boundaries.
|Tweener has some convenience functions to elevate a planar Tweener to a topographic one (isolines).
|The convenience elevation function features a "shape" parameter to control the convexity.
|Tweening from a whole bunch to a whole bunch of curves at once, on a negatively curved surface given by a rotationally symmetric column capital.