oarse cells = n1+1*n2+1</span>
n = [3,3];

<span class="comment">% tag for the coarse grid.</span>
tag = 3;
makeCartFrac(n,tag,box,<span class="string">'cartCoarseGrid.mat'</span>)
fset{3} = struct(<span class="string">'fractures'</span>,<span class="string">'cartCoarseGrid.mat'</span>,<span class="keyword">...</span>
    <span class="string">'box'</span>,box, <span class="keyword">...</span>
    <span class="string">'precision'</span>,1e-3, <span class="keyword">...</span>
    <span class="string">'apertur