Enigma Box

The Enigma Box is a black cube that when filled to a 500mls water comes out the bottom yet when your pouring you still hear water splashing it lets no water out. I think the box uses pressure to keep the box from leaking by curving up and when there is enough pressure it pushes the curve down and lets water out the bottom. when solving the enigma box you need to use observations and infrences yo figure how the box works you need to observe how much water poured into the box