Fantastic type experiments from Merci Bernard

Polygraph makes it possible to transform any letter into another when you walk around it. This system is composed of two elements, a wooden structure, and square modules of varnished paperboards, each painted with a black line, curve or angle. Each letter is made up of six parts. The various modules on offer (square, full, curved, etc.) make it possible to obtain many different letters. The four sides of the structure permit to show four different letters or signs, that the passers-by can read only when they are in the right direction. Polygraph is sold in a box, explaining how to build the wooden structure, and it contains a hundred printed modules.

Via The Serif