"niggli.puzzle" is a new challenge for the sporty eye. Unlike traditional jigsaw puzzles, in which the shapes of individual pieces assist the eye, it features only two forms: square and circle. In this way, it is not evident which pieces belong to the border of the image, which makes the solution of the puzzle more difficult. All pictures represent materials: small-sized textures of wood, glass, paper, and metal in great numbers. All five jigsaw puzzles have this in common; similar forms are repeated many times without ever being exactly the same – an additional challenge to the accuracy of perception. Moritz Zwimpfer is a graphic artist and lives in Basel. He taught graphic design at the Schule für Gestaltung and at the technical college in Basel. At home and abroad, Zwimpfer held workshops and lectures on colour and the didactic principles behind teaching design. As an author of numerous books, he has been working on different aspects of visual perception.