3    dimension

-1.0 -1.0 -1.0   x_low
 1.0  1.0  1.0   x_high
 100  100  100   num_cells
   1    1    1   num_ghost_cells

5    number of grids

-0.8 -1.0 -1.0   x_low
 0.0  0.0  0.0   x_high

 0.0  0.0  0.0   x_low
 1.0  1.0  1.0   x_high

-0.5 -0.5  0.0   x_low
 0.9  0.0  0.5   x_high
 
 0.0 -0.5 -0.5   x_low
 0.9  0.9  0.0   x_high

-0.5  0.0 -0.5   x_low
 0.0  0.5  0.5   x_high
