If the $[a_1,b_1], [c_1,d_1],[a_2,b_2], [c_2,d_2]$ intervals such that
$P_2 = [a_1,b_1] \times [c_1,d_1] \subset \mathbb{R^2}$
$ P_1 =[a_2,b_2] \times [c_2,d_2]\subset \mathbb{R^2}$
And such that $P_1 \subset P_2$. Therefore $[a_2,b_2] \subset [a_1,b_1]$ and $[c_2,d_2] \subset [c_1,d_1]$
I was wondering If there is a way to write $P_2 \setminus P_1$ in the form af a disjoint-union of cartesian products of intervals.
Is there a formula for such a way of writing $P_2 \setminus P_1$