With a bank note: fold the short side of it about 8 mm, then fold the successive 8 mm in the opposite way ecc. At the end you have a kind of "folding door". Then you connect the two short ends of the bank note and you have a kind of "toothed cylinder" one base of which is put horizontallly on a table; then you slowly put an object (a glass for example) trying to find its correct horizontal position on the folded bank note with slight corrections (or it will fall down). It requires some practice. I usually use a 10 € bank note.