Step 9
: Make a crease along the dotted line.
Step 10
: Make a crease along the dotted line.
Step 11
: Fold both the left and the right corners of the upper layer to center line, a triangle will protrude in the middle.
Step 12
: Press the triangle to the right.
Step 13
: Fold the left corner of the upper layer to the right corner.
Step 14
: Repeat step 6 to step 14 to fold the left side.
Step 15
: Make creases along the dotted lines as shown below.