The object to this puzzle is to figure out what is in the cardboard box!

Inside the box is an object that will fit into all 3 shapes shown on the puzzle: a square, a circle, and a cross. The object will completely fill all 3 shapes as it is inserted, it will conform to the edges and leave no voids.

Seems impossible, but isn't. Can you figure out what the object would look like without opening the box? Great puzzle for all you mechanical types, engineers, draftsmen, and anyone who likes a mystery.