+ *
+ * In the returned mesh, the nodes are ordered with the first axis varying first: (X0,Y0), (X1,Y0), ... (X0,Y1), (X1,Y1), ...
+ * and the cells are ordered with the same logic, i.e. in (i,j) notation: (0,0), (1,0), (2,0), ... (0,1), (1,1), ...
+ *