Geometric shapes, I have created one that has a point every 20 degrees. Mine is a 30 pointer. I can see in mine a lot of lines, there is 29 different diagonal lines coming of of one point. I have used a protractor to get my 20 degrees , I have used my ruler to find the middle and do all the lines.
A easy way to find the middle is fold the piece of paper one time both ways. My circle is 360 degrees all the way around which makes it 180 halfway.