Knot(pos: Vector2d, deriv: Vector2d = Vector2d(), secondDeriv: Vector2d = Vector2d())
Knot(x: Double, y: Double, dx: Double = 0.0, dy: Double = 0.0, d2x: Double = 0.0, d2y: Double = 0.0)
Class for representing the end points of interpolated quintic splines.