Get the overlapped faces


I would like your help to get overlapped faces.
For example, I have four pieces of blocks and there are four contact faces. I want to get the overlapped shaped faces like below. (17.9 KB)

Thank you.

The definition have two ways if you want extract overlapped faces or just find the intersections (31.5 KB)


Thank you very much.
That is exactly what I wanted. I really wanted to find a function like Brep/Brep fuction.
Thanks again. Have a great dady.