MATHEMATICS AND ORIGAMI

Jesús de la Peña Hernández

Thus, mountain and valley folds in Fig. 3 are what we need to get a flat-folded figure. We may

observe that the four marked angles are supplementary, for the double of their sum adds up to

360º. Fig. 4 shows the flattened quadrilateral with a view of its internal folds.

Interlude

B

I

A ́

C

3

A

view along X

I

A ́

A

A ́

X

4

B

C

A