Here's another theoty about the ORIGIN of the jewish star:
Shulamit Gad quotes in her book (published in 2006) King David and the Power of Psalms in page 706 from Rabbi Yosef Bagad’s book titled Yosef Nachalah page 773 that the tabernacle's roof was covered with cut leathers in the shape of isosceles but not equilateral triangles. These triangles were placed one on top of the other in the shape of a prolonged Star of David.
This blog (by Zeev Barkan) is dedicated to the Star of David, its history, its various meanings and usages in different cultures. It includes thousands of pictures of Star of David, six-pointed stars, hexagrams, Solomon's Seals, Magen Davids and yellow badges,and served as a resource for three books and four art exhibitions.