Only the front of the square piece of paper is coloured.
Step 1:This is the front of the paper.
Turn the paper.
Step 2:
Make mountain- and valley-folds over these 4 lines.
Unfold each fold after you've made one.
Step 3:
First, make 2 valley-folds below, on the left.
Then, make 2 mountain-folds in the middle.
And make 2 valley-folds on top, on the right.
Now you get a basic-shape.
Step 4:
Make these folds over the upper 2 layers of the model.
Step 5:
Unfold the folds you've made in step 4.
Step 6:
Pull the end at the bottom of the arrow upwards by making
a valley-fold over the yellow line.
Step 7:
Press the edges that stand upwards flat from above,
see the purple arrows.
Step 8:
Now the model looks like this.
Repeat step 4 to 7 on the backside of the model.
Step 9:
Fold the end above the yellow line downwards by making
a valley-fold over this yellow line.
Do the same on the backside of the model, see arrow.
Step 10:
Fold the piece on the right of the yellow line to the left
by making a valley-fold over this line.
Step 11:
Fold the end below the yellow line upwards by making
a valley-fold over this yellow line.
Step 12:
Make a valley-fold over the yellow line.
The corner on the left-side of the model is pulled upwards
when you make this fold.
Step 13:
Press the edges that stand upwards flat from above,
see the purple arrows.
Step 14:
Repeat step 12 and 13 on the right-side of the model,
see the yellow line.
Step 15:
Repeat step 11 to 14 on the end at the backside of the model,
see the purple arrow.
Step 16:
Fold the piece on the right of the yellow line to the left
by making a valley-fold over this yellow line (=bookfold).
Do the same on the backside of the model.
Step 17:
Fold the piece below the yellow line upwards by making
a valley-fold over this yellow line.
Step 18:
Repeat step 17 on the end at the backside of the model,
see purple arrow.
