B-Spline Curve with Periodic Knot Vector
This cubic B-spline curve consists of a single segment. It is determined by four control points (shown by the locators) and a periodic knot vector. The knot vector, in particular, knot intervals 1–7, determines the parametrization of the basis functions. The curve segment is generated on interval 4. You can change the parameter intervals and watch their effect on the curve (1 and 7 do not influence the curve).