a different challenge

A colleague brought an interesting puzzle to solve.
I like the fact that you can always remove any part of this puzzle, even the first one you put, it's not stuck under the next ones. It gives you the impression that it's very easy and you can solve it within minutes. err....
Sadly, I realized I wouldn't have enough time IMO, so I went for the bruteforcing - and learned to make shallow copies of lists :)

codesource (python) here