Cut the cardboard to perfect squares.
Decorate each sheet of cardboard.
Fold the square diagonally from one side to the other and then do the same to the other side. So you will have a cross on the square.
Cut in from each corner to about halfway up. Do not cut too high up.
Make a small hole in the centre of the square (where the two folds intersect). Make a small hole on the tip of alternating corners.
Fold the corners with a hole to the centre. Place the split pin through the holes and open at the back.
Make a hole through the straw and push the split pin through as well.