Step 10
: Unfold.
Step 11
: Make a crease by folding the bottom left edge to the crease along the dotted line.The folding of the bottom right edge is the same as that of bottom left edge.
Step 12
: Fold on the crease.
Step 13
: Pull out along the creases made in step 11.
Step 14
: Turn over.
Step 15
: Make creases along the dotted line.
Step 16
: Fold according to the valley fold lines.
The black dotted line is valley fold line.
The red dotted line is mountain fold line.