Create a square piece of paper or card and fold into a triangle

Fold paper as shown


Cut along line
Pull only the outer upper triangle back so you end up with a big triangle


Make a new square by folding the outer triangles up






Create a square piece of paper or card and fold into a triangle
Fold paper as shown
Cut along line
Pull only the outer upper triangle back so you end up with a big triangle
Make a new square by folding the outer triangles up