21 panels is a small woode house originally created for the Alp installation. The construction is based on a time saving prefab system joined by a simple concept of hooks and slots. Nails or screws are redundant. The name '21panels' is based on the amount of standard plywood panels (1220 x 2440 mm) required for one house. The wooden components are cut by a cnc milling cutter, keeping the waste material at a minimum. The number of loose parts is kept low, in order to simplify construction as well as production. One house can be assembled in thirty minutes.