In this 1957 Disney educational film on mathematics, Donald Duck learns basic concepts that are usually taught in esoteric circles such as the Pythagorean theorem, the mathematical complexity of pentagrams and the Golden Ratio. These are the basics of the ancient art of sacred geometry. To learn these things, Donald Duck even had to join Pythagoras’ secret society, which distinguished its initiated with the symbols of the pentagram. Interesting video on concepts that wouldn’t be touched by today’s children TV shows with a 10 foot pole.