The Prime radicals. Thinking inside the box

Summary/Review: Uncle Norm needs to mail a top secret package, but there's a problem. The item he's sending is not regular, and it won't fit into an ordinary box. The Rads will have to make their own. They call in a box designer who explains how boxes are made. They learn about certices, faces and edges and discover the wonder of turning a flat, 2D template into a 3D solid shape.