"x-spline-curves">3. X-spline curves</a>
    </h2>
    <p>
    Following 
    <a href="#blanc+schlick">Blanc and Schlick, 1995</a>,
    a (two-dimensional) 
    spline is a planar parametric curve 
    that is based on a discrete set of <em>control points</em>,
    \(P_k \in \mathbb{R}^2\), and a discrete set of <em>blending functions</em>,
    \(F_k : [0, 1] \rightarrow \mathbb{R}\), as follows:

    $$C(t) = \sum_{k=0}^n F_k(t)P_k, t \in [0, 1]$$
  </p>
    <p>
    The definition of an X-spline reparamete