Calculates a curve between two points so that the curve has your specified "target length". The "recklessness" is used in adjusting the curve towards the desired length. A real string hangs in a catenary curve that's mathematically a segment of a hyperbolic cosine. This curve is a parabola, which is much simpler to calculate and adjust, and makes a pretty close approximation. Coming next: 1) moving the endpoints. 2) string lying on the ground??
