oint on the original curve and \(d(t)\) is a function that
    defines the offset at any point on the original curve.
  </p>
    <p>
    In order to find the unit normal function,
    we must first obtain the unit tangent
    function.  This requires differentiating the original curve
    and then dividing by the magnitude of the derivative:

    $$\mathbf{e}(t) = \frac{\mathbf{r}'(t)}{\left\Vert\mathbf{r}'(t)\right\Vert}$$
  </p>
    <p>
    Because the unit tangent function has fixed length, its derivativ