 share endpoints. Given an anchor point which two curves of a spline share, if the control point of one lies in the exact opposite direction of the other control point, the resulting spline will be smooth. If the control points are not only in the exact opposite directions but are also the same distance from the anchor point, then not only will the resulting spline be smooth, but its derivative will be smooth as well. </P>
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We call smooth splines with smooth derivatives &quot;very smooth,&quot; and this 