1.Fold (mountain fold) the paper in half.
2.Unfold the paper so that you can see the crease that you have just made.
3.Rotate the paper by 90 degrees and fold the paper in half.
4.Unfold the paper and there are two creases (horizontal and vertical lines).
5.Rotate the paper by 45 degrees and then fold the paper in half.
6.Unfold the paper and see the diagonal crease.
7.Rotate the paper by 90 degrees and fold the paper in half.
8.Unfold the paper.Now, we have four creases.
9.Rotate the paper by 45 degrees and fold the paper in half. Prepare for a valley-fold.
10.Valley fold according to the step #9.
11.Turn the paper over and prepare for a valley-fold on an exisiting crease.
12.Valley fold according to the step #11.