(１９)
Put the paper like this picture.
(２０)
Make mountain-folds on the blue lines and a valley-fold on the yellow dotted line.
Also, move the right and left to the center.
(２１)
Make mountain-folds and a valley-fold and move the right and left like this picture.
Then fold the two flaps in the direction of the arrows.
(２２)
Fold the two flaps like this picture.
(２３)
Then make a crease at the dotted line.
(２４)
Fold the paper like this picture.
(Fold the bottom to the left.)
(２５)
After making a crease, turn the paper over in a horizontal direction.
(２６)
There are the two flaps on the right because you turn the paper over in a horizontal direction.
Make creases at the dotted lines.
(２７)
Fold the paper like this picture.
(Fold the bottom to the diagonal crease.)
(２８)
On the other side, fold the paper like this picture.
(Fold the bottom to the diagonal crease.)
(２９)
After making creases, turn the paper over in a vertical direction.
(３０)
There are the creases, which you have made in the previous steps, on the top because you turn the paper over in a vertical direction.
Fold the two flaps on the dotted line in the direction of the arrow.
(３１)
Fold the two flaps like this picture.
(３２)
Then make a crease at the dotted line.
(３３)
After making a crease, turn the paper over in a horizontal direction.
(３４)
There are the two flaps on the right because you turn the paper over in a horizontal direction.
Make creases at the dotted lines.
(３５)
After making creases, spread the paper.
