1. Cut the polyhedron into plane figures along the edges of the polyhedron, and several plane figures can also form a polyhedron;

2. When the same polyhedron is cut along different edges, the plane development diagrams obtained are different, that is to say, the same three-dimensional figure can have many different development diagrams.

note:

Memory formula of (1) cube expansion head:

The cube box is cleverly unfolded, with six sides and seven knives;

About 14 sides of cloth, eleven kinds of pictures are clear;

Four-line two-phase defense, six kinds of graphics skillfully combined;

The prancing horse skidded and fell apart; Staggered step by step.

The opposite sides are not connected, and the arrangement of "7", "concave" and "field" is ingenious.

② In the expanded diagram of a cube, there are no more than four small squares on a straight line.

(3) The unfolded diagram of the cube will not have the shape of "field" or "concave". For more knowledge points, you can pay attention to the mathematics course in the general education of Beijing New Oriental Middle School, and I believe it can help you.