MOD19 - MODULAR ORIGAMI - FOUR SQUARE BOX OR LID

Credits and Resources:
Text-Only Instructions: Lindy van der Merwe - Copyright 2024
accessorigami.com
with thankful acknowledgement to Nishi Sakpal for her much appreciated advice and assistance

If you are aware of any source where this model or similar might be listed, please let me know so I can reference it under this heading.
Paper to be used: 4 squares of similar size; use large paper to practice with at first.
Thicker paper or thin cardstock is recommended.
Folding level: Beginner to Intermediate
Steps: 18
Description: This is a modular origami model, meaning that it is made up of different, similar folded units, which are fitted together to form the finished model.
The model is an open, square box with smooth, straight sides.
The bottom of the box is made up of 4 triangles that are arranged in a kind of pinwheel formation.
A lid can be created by folding 8 squares and assembling the bottom and lid of the box separately. See Step 18 for more information.
This design is a variation on some similar boxes using 4 modules, but with a locking fold added to make the finished box or lid more secure.
You can also fold this model as a lid for other square boxes, though some trial and error may be involved to get the sizes of your folding squares correct.
When you have become familiar with assembling the units, you might like to try and use more than one color when designing your modular box and/or lid.
Keep in mind that although this model is fairly secure, its base is made up of different units, so it will not be as strong as a box folded from a single sheet of paper.
You might want to secure the bottom of this box for durability's sake, either by using tape or glue or by adding an extra folded or cut square base placed on the inside or outside of the folded model.
PHASE 1: CREATING THE UNITS:
You will be folding 4 similar units to form your box.
It is recommended that you fold all 4 pieces before attempting Phase 3, which will explain how to fit the pieces together to form the finished model.
If using two-sided origami paper, lay your paper with the patterned or colored side down before starting to fold.
Step 1
Place a square down with its edges to the left and right, top and bottom.
Step 2
Fold the square in half from top to bottom, unfold and then from left to right, unfolding again.
Your square will have one horizontal and one vertical crease line.
Step 3
Now fold the top edge down to meet the center horizontal Crease.
Crease and leave folded.
Step 4
Next, fold both bottom corners of your model inwards and upwards so they  meet each other along the center vertical crease.
They will also meet the bottom edge of the top folded rectangle.
Crease well and leave folded.
The shape will be made up of two triangles at the bottom and a long rectangle at the top of the model at this point.
It should still lie flat on your folding surface.
Step 5
Fold the left edge of the model over to meet the right edge, but crease only the top half, from the top of the model until you reach the center horizontal fold line and then unfold.
Step 6
Now, fold the two triangles at the bottom upward so they cover the rectangle part of the shape.
Notice that two small triangles will still be visible at the left and right sides of the large, central triangle you have just folded up.
Step 7
Fold and unfold just the left small triangle so it folds over the large triangle.
We will refold this small triangle, which we will call triangle A in Step 10 below.
Explanation
We will now be starting to form our flat model into a 3D unit.
Focus on the large, central triangle. It is divided by a central vertical line that should be slightly raised up or in origami terms, it is a mountain fold.
We want to create a new crease on the right half of this large triangle, which will do two things:
It will make a small triangle on the inside of our unit and it will tilt our flat shape into a 3D unit with a 90 degree corner.
Step 8
So, grasp the large triangle at its point that is furthest away from you and lift it back up so it is standing straight up, like a wall.
Then, hold the point and bend the paper all the way, straight to the right while you force the extra paper away from you until the mountain fold of the large triangle lies flat.
The result should be that the right side of the large triangle will fold in half to the right, forming a smaller, multi-layered triangle that will have formed on the side furthest away from you.
At the same time the unit will become 3D since a fairly large triangle will now be standing up nearest you and on the left, there will be a rectangle that is also standing up at a 90 degree angle in relation to the folding surface.
Put in another way, when you take the point of the large triangle and bring it towards you, you want the mountain fold to tilt to the right until it meets the bottom edge of the model, that will be on the table.
Step 9
Let the entire shape flip back towards you so it lies flat on the table again.
The two rectangles, one on the left and the other furthest away from you, will flip into place when you perform this step, forming the first two walls or sides of your first unit.
Lightly press the sides into shape if necessary. You should have a nice 90 degree corner.
On the inside of the two walls, lying flat, you will have a large triangular shape that will become part of the bottom of the box.
If you look at the far wall of the unit, you will find the multi-layered small triangle that you created in the previous step. We will call this Triangle B. It should stand up against the far wall of your 3D unit.
Step 10
The last step for your unit is to work on Triangle A, for which you created a crease line already in Step 7 above.
This triangle will now be on the very end of the left wall of the unit, nearest you
Important: Refold Triangle A away from you so it folds at a 45 degree angle to the outside of the left wall of your unit.
This is a mountain fold, away from you.
Your first module is done. Set it aside for now.
PHASE 2: FOLD MORE SIMILAR UNITS
Repeat steps 1 to 10 3 more times so you have 4 similarly shaped units to work with.
PHASE 3: ASSEMBLING YOUR MODEL
Step 11
Position your 4 units in a loose formation so they represent the four corners of the box. You will have the sides or walls of the units in an upright position with the triangles that will form the bottom of the box , on the table.
Step 12
Explanation
Concentrate on the outer sides or walls of your box. They are made up of two layers, forming pockets, with flaps on the inside that can be lifted.
Also notice the two triangles of each unit. As you join the units, the triangles will act as locks for each module.
You will be starting with the two units furthest away from you. Mentally number the unit on the left as unit 1 and unit 2 will be on the right.
Step 13
To join the first two units, hold unit 1 steady.
Lift and hold Triangle A at the end of unit 2 up, while sliding unit 2 on the inside of the wall of unit 1.
The back wall of unit 2 will pass in front of Triangle B.
Slide unit 2 in as far as it will go. It will be stopped by the corner of unit 1.
Now, tuck Triangle A of unit 2 down so it hooks behind Triangle B of unit 1.
If you pull unit 2 gently to the right, it should hardly move since it has been locked into place now.
The hooked triangles should stay in place for the next step.
Step 14
Now, you need to gently lift the flap making up the back wall of unit 1 as much as possible so you can slip it over unit 2 while also covering both Triangles A and B.
As you do this, the triangles forming the bottom of the box will also slide into place on top of each other.
Step 15
Rotate the corner you have just assembled 90 degrees to the left and repeat Steps 13 and 14 two more times until 3 corners of your box have been tucked into place.
Always slide the new unit on the inside of the model, making sure the triangles lock and then tucking over the flap of the existing unit so it covers the new unit and both triangles.
Step 16
For the last unit, place it on the inside of your box shape and tuck it under the existing side wall as before.
You will notice that you now have two walls next to each other on the right side of your box shape. In order to finish the assembly and to secure the units, the two walls have to switch places.
So, holding the model in your hands, secure the left side while gently pulling the right side apart, but only so you can move the inside wall to the outside. Once this is done, you can tuck the new inside wall underneath the outside flap.
You will know that the box has been folded correctly if all sides and corners look the same and slot together nicely, and there are 4 creases, all facing in the same direction, at the bottom and on the underside of the box.
Step 17

Check the outside corners of your model. If preferred, you can fold each loose corner at a 45 degree angle using a valley fold. Then, use this same crease to tuck the loose flaps under, towards the inside, using a mountain fold.
This will hide the loose corners, create a nicer look and may improve the stability of the model as well.
It might take a few tries for this box to look really neat, since the right kind of paper and strong, accurate folding of each unit is required. Also, as you may realize, the units should not be distorted while being assembled, something that will take time to master as well.
Step 18
To make a lid for this box, repeat all steps with 4 more squares of paper. Because the assembled model is fairly flexible, the lid need not be folded larger than the box itself.
Making origami accessible through text instructions.
for non-commercial use only.
Compiled by Lindy van der Merwe - March 2013
Revised: August 2024
This text copyright 2024 by accessorigami.com

Comments