Credits and Resources
Text-Only Tutorial copyright 2026 by Lindy van der Merwe and Nishi Sakpal
Please note: This tutorial only covers the assembly of a 30-unit regular dodecahedron from the Pentagon Module within the Penultimate unit family.
For a tutorial on how to fold the actual module and other units within the Penultimate Unit family, visit the following page:
Penultimate Unit Family by Robert Neale
Paper to be used: 30 squares of similar size; use large paper to practice with at first.
Note that some tutorials recommend using a rectangle made by first accordion-folding a square into fourths and then removing one of the panels. Accordion-folding a square will form a stronger structure, but if using thicker paper, you may want to have only three layers. The choice is yours.
Folding level: Beginner/Intermediate
Introduction
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.
There are a myriad of unit types and variations. This tutorial describes the assembly method for a 30-unit regular dodecahedron, one of the five Platonic solids. It has 12 flat, regular pentagonal faces, 30 straight edges and 20 vertices or corners.
Since this is an "edge" unit, the finished dodecahedron features a sturdy frame with a pentagonal or five-sided "cutout" that is positioned perfectly on each face of the shape, making it a great choice for a decoration with or without a flameless candle, LED or similar light source placed inside.
You will need 30 or more already-folded Penultimate Pentagon (108 degree) Modules from the following page:
Make sure all units look exactly the same when in their flat/2D as well as their halfway unfolded/3D state.
Because our units are multi-layered, they will have pockets that have formed along their long edges. The short ends of the units or the end tabs will be inserted near the corners into these long edges to form the geometric shape.
Furthermore, we will build the model in rows, starting from a base row and closing the hollow shape at the top.
As always, remember that the following is just one method of assembly. Once you understand the basic structure, you can assemble your dodecahedron in any way you find is easiest for you.
This tutorial is divided into 5 parts: Rows 1, 2, 3, and 4, followed by a detailed summary of the construction steps.
Note that all actions are marked with a star character (*) in the steps that follow.
Row 1 - Ring with 5 Pillars using 10 units
Corner 1
You will be connecting three units to form your first corner.
1.1 Placement
Hold unit 1 in your left hand in portrait orientation. Turn the unit so that one of its end tabs is facing you. Its long center fold will be a valley fold at this point. The unit will have a wall part on the left and a floor part on the right.
Place your cupped right hand over unit 2, holding it in landscape orientation. Its end tabs should also face towards you with the long center fold being a valley.
1.2 Joining
To join the two units, do the following:
With your left hand, find and slightly open the pocket along the right edge of unit 1.
Now, open the end tab of unit 2 with your right thumb and slide it into this pocket.
You are temporarily forcing the end tab of unit 2 flat so you can start the insertion and then letting it bend back into the angle we want.
Slide the end tab of unit 2 all the way to the left and towards you, as far as it will go. It may take some time for you to get used to the specific angle that is required for unit 2 to settle completely into the corner pocket of unit 1. You should feel a satisfying "locking" motion as the first two units move into place. The nearest tab of unit 1 will be left unconnected for the moment, while units 1 and 2 will be joined at a 108 degree angle, forming the first connection.
1.3 Adding unit 3
The first two units will be forming a print L shpe. Unit 3 will be added at the corner nearest you, just where the two arms of the L shape are joined.
Hold unit 3 in the same way as you held unit 2.
Open the long edge of unit 2, nearest you, and slide the end tab of unit 3 into it.
You might have to pull the tab of unit 1 out of the way, towards you when opening the right edge of unit 2 since unit 3 needs to slide in right near the place where the first two units are already joined. Be careful not to force the units beyond their quite flat 108 degree angles, or your corner will simply disintegrate.
If you find it difficult to do this step on the table, feel free to pick up the assembly and hold it in a way that feels comfortable. You could then place it down again for orientation purposes.
Because of the angles, you should feel another light locking motion as the units bend a little and then settle into place. Don't let go of the assembly yet, though. We still need to do one more step to complete our first corner.
1.4 Locking
After this insertion, the tab of unit 1 will still be unattached, hanging around on the outside of the corner assembly. Only once this tab is tucked in securely, will our first corner be completed.
The tab in question needs to be tucked into the long side of unit 3, which will be nearest us at this point. For this to happen, you will need to hold the already-formed corner in place while carefully bending the tab of unit 1 to be able to insert it into the side of unit 3.
It may help to anchor units 1 and 2 on the table while you perform this action, or you could pick up the assembly and hold it where the first two units are already joined.
Result: First corner formed; we can think of three branches stretching in different directions, with one of them becoming a pillar.
1.5 Explanation and orientation
Before continuing, make sure that each end tab has entered into its adjoining unit all the way and that you don't inadvertently flatten or twist the long edges of the units during the assembly. They should remain folded into a "floor" and a "wall" part. Actually, it helps to reinforce the long folds frequently during assembly. Also make sure you are joining units at their corners and not just on the sides near the corners. You need all three units to slot together correctly and completely to form a neat, strong corner for the dodecahedron.
If it feels like your units won't lock together, it is likely that their center, long spine folds and/or their end tabs have started to flatten out. Either reinforce these folds strongly or consider folding new units that will have strong, crisp creases to work with.
Don't be alarmed if, the first time you join units, the corner disintegrates. It may take a few tries to get a feel for the angles that are needed for a secure corner to form. Feel free to try out different techniques and use what works for you.
Before proceeding, you can gently try to pull your assembly apart. If the units stay put, hardly moving, you have a working recipe for the next corner.
Corner 2
2.1 Placement
Choose any of the 3 branches of your assembly and hold it like you did with unit 1, in portrait orientation. We will think of this as unit 3. Ignore the rest of the assembly for the moment.
2.2 Join unit 4 - a pillar
Hold unit 4 in landscape orientation, like you did with unit 2.
Insert its end tab into the edge of the unit you have chosen.
Reinforce the join and make sure the unit is locked in place.
2.3 Join unit 5
Open the nearest edge of unit 4 and, holding unit 5 in portrait orientation, slide it into the side of unit 4, at the corner nearest you. You might have to pull the tab of unit 3 out of the way, towards you again. You should feel another light locking motion as the units bend a little and then settle into place.
2.4 Locking
After this insertion, the tab of unit 3 will still be unattached, hanging around on the outside of the corner assembly.
The tab in question needs to be tucked into the long side of unit 5, which will be nearest us at this point. For this to happen, you will need to hold the already-formed corner in place while carefully bending the tab of unit 3 to be able to insert it into the side of unit 5.
Result: Second corner formed; there are now 3 branches and 2 pillars completed.
Corner 3
3.1 Placement
You will now be able to recognize that a ring is starting to form. For orientation, place the assembly so that 3 units are touching the table. These 3 units should form what will look like the 3 sides of a square, with the open side nearest you. Furthest away from you, the two pillars we have formed so far will be standing up.
Focus on the unit that is lying flat on the table, on the right of the assembly. We will think of this as unit 5. It will already be in portrait orientation, but you may need to tilt the assembly slightly to the right for the insertion of unit 6.
3.2 Join unit 6 - a pillar
Hold unit 6 in landscape orientation, like you did with unit 2.
Insert its end tab into the edge of unit 5.
Reinforce the join and make sure the unit is locked in place.
3.3 Join unit 7
Open the nearest edge of unit 6 and, holding unit 7 in portrait orientation, slide it into the side of unit 6, at the corner nearest you. You might have to pull the tab of unit 5 out of the way, towards you again. You should feel another light locking motion as the units bend a little and then settle into place.
3.4 Locking
After this insertion, the tab of unit 5 will still be unattached, hanging around on the outside of the corner assembly.
The tab in question needs to be tucked into the long side of unit 7, which will be nearest us at this point. For this to happen, you will need to hold the already-formed corner in place while carefully bending the tab of unit 5 to be able to insert it into the side of unit 7.
Result: Third corner formed; there are now 4 branches and 3 pillars completed.
Corner 4
4.1 Placement
For orientation, place the assembly so that 4 units are touching the table. These units should form a kind of diamond shape, positioned with its only opening nearest you. Furthest away from you, 3 pillars will now be standing up.
Focus on the unit that is lying flat on the table, on the right of the assembly. We will think of this as unit 7. It will already be in portrait orientation, but you may need to tilt the assembly slightly to the right for the insertion of unit 8.
4.2 Join unit 8 - a pillar
Hold unit 8 in landscape orientation, like you did with unit 2.
Insert its end tab into the edge of unit 7.
Reinforce the join and make sure the unit is locked in place.
4.3 Join unit 9
Open the right edge of unit 8 and, holding unit 9 in portrait orientation, slide it into the pocket of unit 8, at the corner nearest you. You might have to pull the tab of unit 7 out of the way, towards you again. You should feel another light locking motion as the units bend a little and then settle into place.
4.4 Locking
After this insertion, the tab of unit 7 will still be unattached, hanging around on the outside of the corner assembly.
The tab in question needs to be tucked into the long side of unit 9, which will be nearest us at this point. For this to happen, you will need to hold the already-formed corner in place while carefully bending the tab of unit 7 to be able to insert it into the side of unit 9.
Result: Fourth corner formed; there are now 5 branches and 4 pillars completed.
Corner 5
5.1 Placement
Focusing on the units that are forming the ring on the table, rotate the assembly until you have two units that are almost touching, but that are not yet connected, in front of you.
Also note that you will have 4 standing pillars now, one on each corner of the shape.
5.2 Connecting units 1 and 9
So, we will first join the units in front of us and then add one more unit to form the last pillar.
To do this, insert the end tab of unit 9, on the right, into the side of unit 1, on the left.
5.3 Unit 10 - a pillar
To complete our fifth and final corner for the ring, we will only be adding one more unit, namely unit 10.
So, holding unit 10 in landscape orientation, insert it into the side of unit 9.
You may once again need to tilt the assembly slightly to the right for the insertion of this last unit. It will form a fifth pillar.
5.4 Locking
After this insertion, the tab of unit 1 will still be unattached, hanging around on the outside of the corner assembly.
The tab in question needs to be tucked into the long side of unit 10, which will be nearest us at this point. For this to happen, you will need to hold the already-formed corner in place while carefully bending the tab of unit 1 to be able to insert it into the side of unit 10.
Strengthen the new corner formed as well as the spines of the new units.
Result: Fifth corner formed; there are now 6 branches and 5 pillars completed.
The base or row 1 of the dodecahedron is now completed.
The flat, five-sided ring you have formed should have a fairly large pentagonal opening at its center. You can easily trace the inside of this ring with your fingers, ensuring it has five sloping edges of equal lengths.
If you pick up the assembly and turn it so the five pillars are stretching away from you, you will be able to view the first of the 12 pentagonal faces of the dodecahedron from the "outside".
Keep in mind that, by forming the pillars, we have already made a start with the creation of 5 more rings, which we will be working on next.
Row 2 - Rings 2 to 6 using 10 units
Place the model with the completed face flat on the table and turned so two of the adjacent pillars are in front of you.
Instead of forming corners, like we did in the first row, from now on, we will be completing actual rings of the geometric shape. Note that for each ring below, as you rotate the model, "unit A" refers to the leftmost standing pillar of that current space, and "unit B" refers to the rightmost standing pillar of that space.
Ring 2
Focus on the space between any two pillars. You will find we already have 3 edges in this space, so we need to add two units to complete the ring.
Focus on the slanted edges of the existing units on the left and right. We will call the one on the left unit A and the one on the right unit B.
Insert the end tab of unit 11 into the long side of unit A.
Insert the end tab of unit 12 into the long side of unit 11, near its right end.
Take the end tab of unit B and insert it into the side of unit 12.
You will now have closed the second ring.
Ring 3
Rotate your assembly to the right so the next half-formed face of the model is in front of you.
You will find we already have 3 units in this space once again.
Insert the end tab of unit 13 into the long side of unit A.
Insert the end tab of unit 12 (from the previous ring) into the side of unit 13.
Insert the end tab of unit 14 into the long side of unit 13, near its right end.
Take the end tab of unit B and insert it into the side of unit 14.
You will now have closed the third ring.
Ring 4
Rotate your assembly to the right so the next half-formed face of the model is in front of you.
You will find we already have 3 units in this space once again.
Insert the end tab of unit 15 into the long side of unit A.
Insert the end tab of unit 14 (from the previous ring) into the side of unit 15.
Insert the end tab of unit 16 into the long side of unit 15, near its right end.
Take the end tab of unit B and insert it into the side of unit 16.
You will now have closed the fourth ring.
Ring 5
Rotate your assembly to the right so the next half-formed face of the model is in front of you.
You will find we already have 3 units in this space once again.
Insert the end tab of unit 17 into the long pocket of unit A.
Insert the end tab of unit 16 (from the previous ring) into the side of unit 17.
Insert the end tab of unit 18 into the long side of unit 17, near its right end.
Take the end tab of unit B and insert it into the side of unit 18.
You will now have closed the fifth ring.
Ring 6
Rotate your assembly to the right so the last half-formed face of the model is in front of you.
You will find we already have 3 units in this space once again.
Insert the end tab of unit 19 into the long side of unit A.
Insert the end tab of unit 18 (from the previous ring) into the side of unit 19.
Insert the end tab of unit 20 into the long side of unit 19, near its right end.
Take the end tab of unit B and insert it into the side of unit 20.
Finally, insert the end tab of unit 20 into the side of unit 11.
You will now have closed the sixth/final ring of row 2.
You have used 20 units and have constructed 6 rings so far.
Row 3 - 5 units
If you place your structure with the first ring we built flat on the table, you should be able to find 5 closed rings and 5 pointy ends standing up in a circle. These end tabs, which we will call the "standing tabs" are where 5 more rings have started to form, so they are where we will focus next.
We will now be adding units 21 to 25.
Choose one of the standing tabs and focus on the long sloping edge of the unit just to the right of this tab.
Insert the end tab of unit 21 into the long side of this existing unit.
Then insert the end of the standing tab into the side of unit 21.
You will have formed another, longer standing tab now. It will seem to hang in the air. As you add more units in this row, it will start to seem as if the standing tabs are overlapping each other. Just try to ignore this for the moment and continue in a circle, adding one new unit to each existing standing tab as described above.
At the end of this process you will have added units 22, 23, 24 and 25.
Row 4 - Closing - 5 units
In this last row, we will be closing the remaining 5 rings of the model and building the last of the twelve rings in the process.
Your structure will now have taken on a fairly rounded shape with 5 end tabs almost touching near the top of the shape. The units may seem to have ended up overlapping each other, but try to just work with two adjacent units at a time, ignoring the rest of the units, and all will be well.
Unit 26
Choose one of the standing tabs and focus on the long sloping edge of the unit just to the right of this tab.
Insert the end tab of unit 26 into the long side of this existing unit.
Take the end tab of the existing unit on the right and insert it into the side of unit 26.
You will have closed the seventh ring.
Units 27 to 30
In a similar way, add unit 27 to close the eighth ring, unit 28 will close the ninth ring and unit 29 will close the tenth ring.
Take care to tuck in all the remaining tabs of the assembly as you go.
Unit 30 will close both the 11th and the 12th rings.
Your model is complete. Check all the corners to make sure no end tabs have slipped out of place during the assembly. Each of the 12 flat faces should have a perfectly formed pentagonal opening.
Summary for construction of the dodecahedron from Penultimate Pentagon Units
Row 1
Corner 1: Place unit 1 in portrait, add unit 2 in landscape, add unit 3 in portrait.
Corner 2: Add unit 4 in landscape as a pillar, add unit 5 in portrait.
Corner 3: Add unit 6 in landscape as a pillar, add unit 7 in portrait.
Corner 4: Add unit 8 in landscape as a pillar, add unit 9 in portrait.
Corner 5: Add unit 10 and close ring 1 by connecting units 1 and 9.
Row 2
Ring 2: Add unit 11, add unit 12, add existing unit into unit 12.
Ring 3: Add unit 13, add unit 14, add existing unit into unit 14.
Ring 4: Add unit 15, add unit 16, add existing unit into unit 16.
Ring 5: Add unit 17, add unit 18, add existing unit into unit 18.
Ring 6: Add unit 19, add unit 20, add existing unit into unit 20.
End the row by tucking in the tab of unit 11 into the side of unit 20.
Row 3
Add units 21, 22, 23, 24, and 25 to each of the five end tabs that are standing up, tucking in tabs as you go.
Row 4
Add unit 26, add existing unit into unit 26.
Repeat with last 4 units to close rings 7, 8, 9, 10 and 11 while (at the same time) building ring 12.
Tuck in all remaining tabs.
Making origami accessible through text-based tutorials.
For non-commercial use only.
Compiled by Lindy van der Merwe and Nishi Sakpal - May 2026
This text copyright 2026 by accessorigami.com and the authors.
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