,box, <span class="keyword">...</span>
    <span class="string">'precision'</span>,1e-3, <span class="keyword">...</span>
    <span class="string">'aperture'</span>,0.0005, <span class="keyword">...</span>
    <span class="string">'tag'</span>, 2 <span class="keyword">...</span>
    );


<span class="comment">% make an nonconforming coarse grid for comparison</span>
<span class="comment">% for simplicity we use a Cartesian coarse grid</span>

<span class="comment">% number of internal points i.e number of c