lculation of the left offset for a fixed offset
    (the unit normals are green lines and the left offset curve is red).
  </p>

    <p class="img">
      <img src="figure/render-fixed-offset-1.svg" width="30%">
    </p>
    <h3>Specifying the amount of offset</h3>
    <p>
    The offset curve equation consists of the original curve plus
    the unit normal function mulitplied by a function, \(d(t)\), that
    specifies that amount of offset at any point on the original curve:

    $$\mathbf{r}_0(t)=\mathbf