Credits and Resources
Text-Only Tutorial copyright 2026 by Lindy van der Merwe
Various sites show how to fold this unit. See, for instance:
These instructions describe how to fold various units that are all part of the Penultimate Unit family, originally developed by Robert Neale and that may have been discovered independently by various other origamists.
You can find Robert Neale's ebook "..." at the following link:
Lots of geometric shapes can be made by combining different units within the family.
For some excellent tutorials, examples and ideas, you can also visit Michal Kosmulski's page, detailing this unit family:
Paper to be used: squares of similar size; use large paper to practice with at first.
Note some tutorials recommend using three-quarters of a square by accordion-folding into fourths and then removing one of the panels.
Folding level: Beginner/Intermediate
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.
The following units of the Penultimate family are described below:
1. The Pentagon Module (108 degrees)
2. The Square Module (90 degrees)
1. The Pentagon Module (108 degrees)
The method described here is only one way of folding this module. The various units mentioned in these tutorials can be combined in order to form intricate 3D structures of varying complexity.
The shape most people fold first with the Pentagon Module is the regular dodecahedron, a platonic solid with 12 pentagonal faces.
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
If preferred, tear or cut off one quarter panel of your square and continue as follows.
Step 6
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 7
Fold the bottom left corner, all the layers, diagonally up to meet the top edge of the strip, to form a small triangle on the left.
Crease well and unfold.
Step 8
Fold the top right corner, all the layers, diagonally down to meet the bottom edge of the strip, to form a small triangle on the right.
Crease well and leave folded.
Note that some people prefer to unfold the two triangles just created. I prefer to keep them folded for the next step.
Step 9
Now, fold a diagonal valley crease from bottom left to top right. The crease should start at the place where the left diagonal formed in Step 7 meets the bottom edge and it should end where the diagonal crease formed in step 8 meets the top edge.
It is a long, diagonal line that should be creased strongly.
If you leave your triangular tabs folded, one way of accomplishing this fold is to keep the left folded triangular flap pressed flat, while flipping the right triangular flap away from you. The right triangle will flip completely from its original position (on its back) over to touch the table (onto its front.
Take your time with this crease since it is not one often used. It may feel somewhat "forced" in the beginning, until you get used to it. It as to be accurate for all units since if your folding is even slightly off, you will have trouble creating the correct angles when doing the assembly.
Another option is to make this fold while holding the model in the air: first bend the paper near the left corner, pressing firmly with both hands; then rotate the unit 180 degrees and repeat the bending and pressing near the opposite corner; lastly, form a straight mountain fold by extending the bends you have started in order to form an accurate, straight line between the two points you have identified.
Once you have formed a straight, long, mountain crease, press the unit all the way flat. It will now be symmetrical.
The result should look a bit like the side view of a table, with a straight, long edge at its top and two fairly large triangles (the legs) will have formed on the left and right, or you could also say the back and front, of the unit.
If the unit is laying flat on a table, the visible surface will have three areas: on the left, a large triangle with its long base at a slight angle, then a small triangular area that will look like a cutout and lastly, on the right, another small triangle forming the right corner of the shape. We could also think of the shape as the flat roof of a house, with the sides slanting downwards and a little outwards.
Step 10
Finally, as you made this last crease, you would have found that the unit would have shown quite a bit of resistance. This is fine, since you actually would like for it to end up being a 3D shape. So, open the flat shape by bringing its front panel into an upright position.
If you place one long part of the unit flat on the table, the other part will stand up, like a wall, but both will be long triangles instead of e.g. a rectangle.
The tabs at the ends of the units should also be bent at around a 45 degree angle.
This completes the 108 degree module of the Penultimate Unit family.
2. The Square Module (90 degrees)
The method described here is only one way of folding this module. The various units mentioned in these tutorials can be combined in order to form intricate 3D structures of varying complexity.
The shape most people fold first with the Square Module is the cube, a platonic solid with 6 square faces.
Step 1
Follow Steps 1 to 9 outlined above, for making the Penultimate Pentagon (108 degree) Module.
Step 2
Make sure it is placed in its flat form on a table, with the top edge horizontal and the tabs on the left and right.
Step 3
Focus on the triangular cutout or space on the surface of the unit. We would like to unfold the right tab and then refold it so that its edge lines up with the long diagonal edge nearest it.
Actually, we are closing the cutout gap, thereby changing the 108 degree angle of the Pentagon Unit into the 90 degree Square Unit.
Crease well and leave folded. There should now be no space or triangular cutout like you had for the 108 degree unit.
Step 4
Repeat this fold on the opposite end of the unit so it is symmetrical.
You will now have a Penultimate Square Module with nice 90 degree corners. You will notice a small part of the last folds extending beyond the edge of the paper. Some people remove these tiny pieces by cutting, tucking in, or inside-reverse folding, but they can simply left as is, since they will be hidden inside the finished model and will not interfere with the assembly.
Step 5
Unfold the unit halfway so that you have the "floor" and "wall" part visible again.
The tabs at the ends of the units should also be standing at a 90 degree angle.
This completes the 90 degree Square Module of the Penultimate Unit family.
Making origami accessible through text-only tutorials
For non-commercial use only.
Compiled by Lindy van der Merwe - March 2026
This text copyright 2026 by accessorigami.com and the author.
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