Divers lung test magic

This model is a magic trick/prank that I made so that you can play it on your friends. It works by having a main tube that you blow air into, but that tube just blows the air back at you. There is a secret one on the bottom that makes the fan spin. To blow into the secret one you just cover the main hole and blow. There is also an included assembly guide for the easy assembly of this prank.Boost MePlease boost me