The window stars I showed you three days ago were modular, but flat and held together with glue. Today’s modular star is three dimensional and made of five interconnecting units that hold together mechanically.
Instructions for this star can be found in many places on the internet (now including this post), with almost as many credits for its design. I don’t remember where I found it first. The one above was made with 10 cm (4″) origami foil paper and is about 20 cm 8″ across. The foil was difficult to work with (perhaps that’s just me), so I did the demonstration in plain origami paper. It would work with lightweight coloured copy paper as well.
You will need 8 squares of paper. I would not try this with anything smaller than 10 cm (4 inches) on the first attempt.
Take a square of paper and fold it in half from corner to corner.
Open flat, then fold side corners to centre line.
Open flat and rotate 45 degrees. Fold bottom right corner to meet left fold line (indicated by yellow pointy finger). Flatten the fold from the bottom only as far as the upper fold line (indicated by green pointy finger).
The picture below shows how your fold should look when you open the paper again.
Make the next fold from the point indicated by the green pointy finger in the image above to the upper right corner. This is easiest if you pick up the paper and pinch the fold.
When you open your paper again, the folds should look like this.
Now fold the right side in along the pre-existing fold, while bringing the top right corner down to match the side.
Keeping the paper folded, rotate 45 degrees clockwise and then fold left side in.
Fold left side over right.
Rotate 90 degrees.
Fold left end up and a little to the right (green pointy finger) so that the bottom corner now meets the top fold (yellow pointy finger).
Now fold the top point (green pointy finger in image above) down. The fold should match the fold along the length of the unit.
Your unit is complete. Open it so that it looks like this.
Repeat the steps with your other seven pieces of paper. When you are done, you can assemble the star.
Take two units and slide the second into the first as shown below. There is a pocket for the tip to slide into. It’s indicated by the green pointy finger.
It may take a bit of wiggling, but the pieces should slide together.
Try to get the fold on the second piece as close to the edge of the pocket in the first piece as possible. If the join feels a little insecure, go ahead and use a bit of glue.
Repeat until all units are joined.
Congratulations: you have completed the star!
The finished stars look good from both sides, and both surfaces will show the same colour. Here are a couple of small white ones I made to show both sides.
If you enjoyed making that star and would like to try another, here are the two sides of a Robin Star.