compressQTree i t = if(((depthQTree t) - i) < 0)
                      then let (x,y) = sizeQTree t in (Cell (searchCell t) x y)
                         else anaQTree f ((depthQTree t) - i, t)
             where f (_, (Cell a b c)) = i1(a, (b, c))
                   f (0, s@(Block a b c d)) =  let (x,y) = sizeQTree s in i1 ((searchCell a), (x, y))
                   f (n, (Block a b c d)) = i2( (n-1 , a) , ((n-1 , b), ((n-1 , c), (n-1 , d))))

searchCell = cataQTree (either g1 g2)
      where g1 (a,(b, c)) = a
            g2 (a,(b,(c,d))) = a