PHI00 - MODULAR ORIGAMI - THE PHIZZ UNIT BY THOMAS HULL

Credits and Resources
Text-Only Instructions copyright 2025 by Lindy van der Merwe
accessorigami.com
Various sites show how to fold this unit.
For a video tutorial on how to make and assemble the unit presented by Tom Hull himself, visit:
PHiZZ Unit Videos
Note that the presentation has two parts. Both links appear near the top of the abovementioned page:
Written in full, PHiZZ stands for: Pentagon Hexagon Zig-Zag.
Paper to be used: squares of similar size; use large paper to practice with at first.
Since this unit uses paper that is accordion-folded, thinner is better. Yet, you will need paper that will hold creases well, especially if you would like to construct models with many units.
Folding level: Beginner/Intermediate
Steps: 12
Description:
A unit or module in origami is like a puzzle piece. 
To make a modular origami figure, you will need to fold more than one unit and assemble them in a certain way.
These instructions describe how to fold only one type of unit, the PHiZZ module, designed by Thomas Hull.
The method described here is only one way of folding this module. Once the basic unit is folded, it can be modified and connected in different ways to form various complex structures.
Many wonderful origami models have been created using this unit.
For instance, once you know how to fold this module, you will be able to combine 30 of them into a dodecahedron.
If using two-sided origami paper, lay your paper with the patterned or colored side up before starting to fold.
Step 1
Place a square  down  with its edges to the left and right, top and bottom.
Step 2
Make a book fold by bringing the left edge over to meet the right edge. to create a central vertical crease.
Leave folded.
Step 3
Now fold the right edge back over to meet the left hinged edge again.
Crease and leave folded.
Step 4
Flip the figure over from top to bottom and repeat the previous step.
Your original square should now be accordion-folded into fourths, forming a long strip, four layers thick.
Step 5
Rotate the strip so the short edges are on the left and right
It is not critical as to which of the two long edges are facing you, but it will make things easier if you always place your strip in the same way. I like to place my strip with the one hinge fold and the raw edges nearest me.
Note that, for the following steps, we will treat our strip as if it is a single layer of paper.
Step 6
Bring the top left corner, all the layers, diagonally down to meet the bottom edge of the strip, to form a small corner on the left.
Crease and leave folded.
Step 7
Take the remaining long, top edge of the strip and bring it diagonally down and to the left so it comes to rest alongside the first triangle you folded.
The figure will now be made up of a small triangle on the left with another triangle on the right, but this right triangle will extend downwards, towards you, ending in a straight edge nearest you.
Step 8
Now, take the bottom straight edge of the long strip on the right and fold it straight up and away from you, until it is flush with the paper below it.
This means you should now have a triangle on the left and a rectangle on the right. These shapes should share a straight bottom edge.
Step 9
We are now going to fold the top edge of the right rectangle diagonally down and to the right again, to start forming part of another triangle, making sure the bottom edge of our figure is still straight.
It will look like two little peaks, the left one being partially hidden by the right one. The front peak will actually be made up of a triangle that seems to extend into a flat vertical edge on the right of the unit.
Step 10
Flip the unit over from left to right.
Step 11
You have guessed correctly. Our last diagonal fold is exactly the same as the first one we made in Step 6 above, completing our unit, which is now symmetrical.
Step 12
Explanation and Presentation of the PHiZZ unit
When pressed flat, the PHiZZ unit looks like two triangles that are joined by their sides. When folded accurately, the unit should be straight and symmetrical, meaning it will feel the same on the back and front of the flat figure.
Note that for the side facing you, there will be a smooth triangle on the right and the one on the left will have a loose flap that you will be able to lift away from the folding surface.
If you flip the unit over, you will find the exact same construction on the other side.
12.1 Opening:
In order for us to start building with the unit, though, we need to change it back into a strip, but instead of being flat or 2D, it will now have a 3D form.
To do this, pick up the unit and hold it upright, so the straight edge faces the table and the two points should face the ceiling.
grasp the two loose triangles at the sides of the unit and gently move your hands apart as far as possible.
It may feel as if the strip is twisted at its center. If this is the case, let go of one end of the strip so that there are no twisted folds.
12.2 Orientation:
Place your strip down on the table again in the same position as before, i.e. with the short edges left and right and with the one hinge fold and two raw edges nearest you.
Although you want the strip to be fully stretched out, don't press it completely flat. You would like for the mountain and valley folds to keep their shape as much as possible.
With your strip open as just described, you will notice the following:
A. A prominent vertical center valley fold line that divides the unit in half.
This line is important and will be the only valley fold once you open your unit as described above.
It may seem as if the valley fold is diagonal, but if you pull the strip into a flatter shape, you will find that the center valley crease is actually a straight vertical fold.
B. On each side of the center fold there are 3 triangles. that will also seem to form a zigzag pattern.
C. Flaps or points: The two triangles on each end of the strip will form the flaps or points of the units.
D. Pockets: The pockets have been formed by the pleat folds of the unit and may be accessed from both long sides of the strip.
Note that the pockets actually stretch across the length of the entire strip.
You can open the pocket by inserting your finger into the layers of the unit, approaching it from the side nearest you if it is laying in front of you with the short sides on the left and right.
Similarly, you can also access a pocket by inserting a finger from the side furthest away from you.
If you have trouble with this, it helps to start opening the pockets from one of the corners.
NB: However, when doing the assembly, you would like to insert the points of your units perpendicularly into the pockets, close to the central line mentioned in A above.
The locking mechanism for the units will happen when the points are inserted into the pockets, and specifically when the diagonal mountain and valley folds of the two units line up.
So, it is important to have your units in this "open" state for the assembly to work.
Once the unit is folded, take care not to press it flat. The more "springy" the units are, the easier it will be to do your assembly.
This completes the explanation of the PHiZZ unit.
If you would like to make a dodecahedron, you will need 30 units.

Making origami accessible through text-based instructions.
For non-commercial use only.
Compiled by Lindy van der Merwe - January 2025
This text copyright 2025 by accessorigami.com 

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