... flat, but will be concave instead of convex.18.Valley fold the now concave flap down along thecrease made in Step 14, and flatten the model.19.The result. Fold the flap containing the smallpreliminary ... bottoms of the long, rectangular stripsto the center line and unfold.23.24.Quadrisect the angle of the lower end of therectangular flaps. Note that the long, innermost foldsconnect to the ... center and unfold.5.Valley fold, connecting the tops of theangle bisectors, and unfold.Valley fold through a point 2/3 the waybetween the top point and the creaseconnecting the angle bisectors...