How to make a 3D origami tank

(page 9)

15th picture of 3D origami tank

15.

Cut the paper along two dotted lines of the step #14.

Now, you have four small square paper.

Prepare to select one of four.

16th picture of 3D origami tank

16.

Select one of four paper.

Make a "balloon base" from the square paper.

Prepare to apply two valley-folds.