1 vertical black and white version on thin paper
1 horizontal color version on thick paper
Step 1: Wash your hands, breath ...
Do the same symetricaly, it will overlap on a few centimeters.
Fold the long strip in it's center perpendicular to the long side.
Make a preparation diagonal fold before you transform it into a square by folding in the extremities toward the center.
I recommend to use a paper to fold so your nails don't leave traces nor 'paint' the ink all over ... if you're using white paper mmmmmm so beautiful white paper ...