Grab a milk or juice carton and there's a fair chance you'd find that it's from Tetra Pak, a Swedish company that focuses on food packaging and processing solutions. A few months ago Tetra Pak invited ten people from around the world to a package design workshop aimed at brainstorming an improved design to one of their commercial packages. I qualified through their "Can You Fold It?" competition, in which contestants had to dream up a simple but creative way to close the end of a cardboard tube—which is basically what package manufacturers have to do.
Image from "Can You Fold It?" qualification phase
Tetra Pak's pioneering product was the Tetra Classic®, but probably more familiar is the Tetra Rex®.