The Inception Chair by Vivian Chiu has an interesting infinite look when viewed from certain angles – this effect is achieved by putting a chair within a chair that sits within another chair… times 10:
Each chair has hand cut grooves on the inside edges of its seat frame as well as notches in the seat back. These grooves range from 1/2” wide to 1/8” wide. The mechanism works so that the pegs fit into the grooves of the chair one size bigger and slides into place so that the horizontal edge between the chair seat and back line up. The simple mechanism allows the chairs to be taken apart and put together with ease.