Modular Origami - Sonobe Triambic Polyhedron

Modular Origami is a form of origami that utilizes many identical units to create a large geometric piece. Each unit, called a Sonobe unit, is often extremely simple and sturdy, so the resulting structure is strong and stable. This Sonobe unit creates triangular mini-structures, so it can be used to create small cubes to much larger structures with many more faces. As long as each unit is completely identical and well-formed, the versatility of this project can be adapted to many different uses.

In this Instructable, I will be using mostly used Post-Its and 3x3 squares of scrap paper, as it is a good way to reuse trash to make something fun.

Sonobe units need to be made in certain amounts. I made 30, but you can make 6, 12, 90, or 120 units to complete a polyhedron.

Supplies

- Post-It notes (used or unused)

- Or, 3x3 sheets of paper

Step 1: Crease in Half

Crease lengthwise, then open it up again so it is flat. Make sure corners are lined up and edges are aligned as to make a perfect fold.

Step 2: Crease Outer Edges to the Center Line

Open back up so it is flat after creasing.

Step 3: Fold the Corners Inward to Their Respective Quarter Lines

Align the top or bottom edge with the creased line. Always fold the top left and bottom right corners for each Sonobe unit. This ensures that all the units will interlock with each other.

Step 4: Fold the Diagonal Corner Fold Edge to the Quarter Line

The corner flap may poke out a bit under the fold from this step when you attempt the fold, so be careful in ensuring that all folds are near perfect for all units.

Step 5: Fold the Quarter Lines Back to the Center

If the little flap from the last step is messy or out of place, this fold may be slightly disturbed.

Step 6: Fold Corners With No Diagonal Folds Up or Down Completely

Align the top or bottom edge with the side edge. Crease this side particularly well.

Step 7: Tuck Corners Under Pocket

Step 8: Fold in Half

Step 9: Fold the Left Point Up to the Upper Right Corner

Then, turn it to the other side keeping the points in order with the indicated positions.

Step 10: Fold Point a to Point C As Modeled

Step 11: Open Up Last Two Folds, Reveal Sonobe Unit :D

The Sonobe unit utilizes pockets and flaps to interlock as many pieces as you want!

Step 12: Interlock Units Together

Triambic points are made with 3 units interwoven with pockets and flaps. Insert the flap of one unit into the pocket of another. Repeat until an entire polyhedron is made!

Step 13: Finished Product!

Mine uses 30 units, but can be made with different amounts to make different sizes. Experiment with different paper patterns or simply reuse all of your stickies!