This model is a representation of the Penrose triangle, an optical illusion. The Penrose triangle or impossible triangle is an impossible object, i.e. it can only exist as a two-dimensional representation and cannot be constructed in space, since it has an impossible superimposition of lines with different perspective constructions. It appears as a solid consisting of three square-based prisms joined together at three right angles to form a triangle.

Watch the video gif, so you can understand the real illusion.