Step 10 :
Fold the bottom edge to the upper edge along the dotted line.
Step 11 :
Flatten along the arrow.
Step 12 :
Pick up the model and look down from upper.
Step 13 :
Press down the right corner.Then flatten as shown below.
Step 14 :
Put the white surface of the model on the table.
Step 15 :
Flatten.
Step 16 :
Make creases along the dotted line.
Step 17 :
Fold the top edge of the upper layer down along the crease made in step 16.
Step 18 :
Flatten along the arrow.
