Graphic Notation e.g. Stockhausen Studie II

When I a primary school student, I was fascinated by the score --  Graphic Notation -- of Karlheinz Stockhausen. Triangle and square figures are on a musical sheet, instead of traditional musical notes. I wanted to listen to that kind of music. However, in music classes in the primary school, only traditional classical music was taught.
After 20 years old, I had chance to linsten to "Stockhausen: Studie II." I was very fascinated by music, since the music is totally different from the traditional sound such as a piano, violin and so on.

Today, we can easily listen to a lot of pieces of graphic notation on the Internet. It's a great benefit to us.