Both sides of the square piece of paper are coloured.
Step 1:This is the front of the paper.
Turn the paper.
Step 2:
Make a valley-fold over the yellow line.
Unfold this fold after you made it.
Step 3:
Make a valley-fold over this line.
Unfold this fold after you made it.
Step 4:
Make a valley-fold over these 2 lines.
Step 5:
And make a valley-fold over these 2 lines.
Step 6:
Unfold the model.
Step 7:
Repeat step 4 to 6, starting with these 2 lines.
You get a pattern of all prefolded squares after you've
done this, see the picture of step 8.
Step 8:
Make a valley-fold over this line.
Step 9:
Fold the piece on the left of the yellow line to the right
by making a valley-fold over this line.
Make this fold over the upper layer of the model.
Step 10:
Make a valley-fold over the yellow line. Make this fold over
the upper layer of the model.
The piece at the yellow dot is pulled a bit to the left when
you make this fold.
Step 11:
Here a part of the fold in step 10 is already done.
Now press on the place indicated with the yellow dot,
so everything becomes flat.
Step 12:
Make a valley-fold over this yellow line.
This line is on the same place as the edge of the model
on the layer below.
The piece at the yellow arrow is pulled downwards when
you make this fold.
Step 13:
Here a part of the fold in from step 12 is already done.
Now press on the piece at the yellow arrow, so everything
becomes flat.
Step 14:
Repeat step 12 and 13 one more time over this yellow line
at the arrow.
Step 15:
Repeat step 10 to 14 on the other side of the model, see
the yellow line.
Step 16:
Add a little glue to the end at the yellow arrow.
Then, make a valley-fold over the short yellow line.
Step 17:
Make an inside reverse fold over the 3 yellow lines.
Do this by making a mountain-fold over the line in the middle
and a valley-fold over the 2 other lines.
Almost automatically a valley-fold is made over the 2 green
lines when you make this inside reverse fold.
Step 18:
Repeat step 17 over these 3 yellow lines.
Now a valley-fold over this green line is almost automatically
made.
