The design of the Voronoi-Corallo transfers the diagrams of Voronoi and puts this new order in a morphological context. The irregular cellular structure which is reminiscent of coral cuts, is forming and inventing itself and lies as a natural coat around the object, reduced to the essential structure of the functional letter tray. The concept is committed to the classic modernism with the clear basic structure of a simple undisguised cube, shown without unnecessary distraction by concealing ornaments – reduced to the essential natural shape of the cellular structure. The simple implementation of biomorphic structures on an everyday office product. By using a simply piling technique (parallel on top of each other or piled with some offset), Corallo trays can be placed on top of each other and even piled with other standard paper trays.