Hexagon (120 degrees)
This is the easiest variation besides the pentagon. It is a subset of the triangle variation, and it does not require cutting or inside folds.
Prerequisite: A completed base Penultimate unit.
Step 1. Using the top flap only, fold the top edge of the little triangle to the crease sitting at 45 degrees.
Step 2. Still using the top flap, fold the newly formed crease in Step 1 to overlap with the crease sitting at 45 degrees. Keep the fold in place.
Step 3. Fold all remaining flaps down along the crease created in Step 2. You now have a 120 degree angle!