The periscope

I made the periscope. The things you need to make this are: two mirrors, an empty clean milk container, cardboard, scissors, tape, and a ruler. How it works is when you look in it at the mirror, light rays come from the top and go in to your eyes. When you use my project it allows you to see under, over, and around things. Submarines use really big periscopes to see ships and obstacles without getting detected. It could also be used for spying.