Step 1:
This is a standard size printer- / copy paper.
Fold in half 3 times and unfold

Step 6:
The purple triangle ruler is made by folding a paper square in half.
Lay a paper strip along the ruler and glue/tape it to the large strip.

Step 5:
This paper is also prefolded in half 3 times.
Cut of two strips and glue / tape them together.

Step 2:
Cut along the prefolded lines

Step 4:
Make about 26 strips

Step 3:
Fold each strip over these 2 lines

Step 10:
Glue / tape the strips together

Step 8:
Tape / glue about 13 strips to the large strip.

Step 9:
Repeat steps 6 to 8 in the other direction.

Step 7:
Lay the purple ruler next to the first strip, see arrow. Lay a second strip along the ruler and glue / tape it to the large strip too.

Step 15:
Glue / tape the remaining loose crossing points together, see arrows as example.

Step 12:
Fold the upper strip in half over the pink line.
Prefold the lower strip and glue / tape it to the model.

Step 11:
Fold 3 standard printer- / copy papers in half and glue/tape them together.

Step 14:
Cut along these (random placed) lines, cut to the prefolded line of step 12. Then, fold the flaps downwards and glue/tape them together.

Step 13:
Glue / tape both ends together, see arrows.