ier">it</span> <span class="special">=</span> <span class="identifier">maxit</span><span class="special">;</span>        <span class="comment">// Initally our chosen max iterations, but updated with actual.</span>
   <span class="keyword">bool</span> <span class="identifier">is_rising</span> <span class="special">=</span> <span class="keyword">true</span><span class="special">;</span>              <span class="comment">// arc-length increases if one radii increases, so function is rising</span>
   <span cla