Grupa, a studio established by three designers (Filip Despot, Ivana Pavić, and Tihana Taraba) in Croatia's capital Zagreb, are the principle makers behind the minimal Shtef shelving system for Prostoria. Made in collaboration with architecture studio 3LHD, Shtef is a highly modular lightweight system which was designed specifically to be able to adapt with ease to any interior.

The system's basic building element is a rectangular frame with slots that can be mounted on a wall and function as a visually autonomous object. Other compatible L-shaped modules, which come in three different depths and seven different sizes, can be slotted into the basic element to function as shelves. Alternatively, two basic elements can be fused together to create a free-standing shelving system.

This results in an extremely versatile and customisable system that can be constructed and modified to form an infinite number of variations, in combinations ranging from playful and dynamic to clean and elegant.