at $t=\pi/2$,
      $t=\pi$, and $t=3\pi/2$ as well.</li>

      <li>
        <div class="marginpar">
          If you end up with an ellipse and several concentric
          circles, then you've done this right.
        </div>
          In the plane, draw the path of the horse for $t\in
        [0,2\pi]$. Then, on the same 2D graph, include a contour
        plot of the temperature function $f$. Make sure you include
        the level curves that pass through the points in
        <a href="#horse-track-ite