Original method for folding the twenty-sided platonic solid from a single rectangular sheet of a 2:1 ratio. My method features good utilization of the paper and optimization for size, a easy and straightforward prefold sequence, and a very secure lock. In general, folding a polyhedron from a 2:1 rectangle is easier than a square and better utilizes the paper. This is because you have more edge relative to area, and you can use something like a Mercator projection for the layout, or a two-hemisphere clamshell arrangement.