How to make a regular octagon out of square paper

(page 7)

11th picture of regular octagon out of square paper

11.

Valley-fold the paper in half horizontally and then unfold

Prepare to valley-fold diagonally and then unfold.

12th picture of regular octagon out of square paper

12.

Apply the diagonal valley-fold of the step #11 and then unfold.

Prepare to apply another diagonal valley-fold and then unfold.

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