Video narration
How can a flat paper shape become a solid box? Take a paper model. It starts flat, but fold its connected faces along the edges, and they build a closed 3D shape. That flat pattern is a net. A prism has two matching, parallel bases joined by side faces. In a right prism, those sides are rectangles; in more general prisms, they can be parallelograms. Its base shape names the type. A pyramid has one base, surrounded by triangular faces that meet at one point. Different layouts can sometimes fold into the same solid. Here's the important flip: the right faces are not enough. Their arrangement must fold correctly. Do the faces close the solid, without gaps or overlap? So, could this flat paper shape become a solid? Yes-when its faces are arranged to fold together and close it. The pattern reveals the solid it can make.