Recently I tried writing a sound program on ShaderToy and without thinking much assumed you could easily vary the frequency of a tone by using sin( t * freq * tau ) and animating freq. Whoo my ears got a big surprise, and a Google search brought me right to https://www.iquilezles.org/www/articles/fm/fm.htm
He also has some wonderful youtube videos (https://www.youtube.com/watch?v=62-pRVZuS5c).
I cannot recommend his website enough for folks getting into lower-level graphics development!
I stumbled upon the channel one or two years ago, very interesting stuff if you are into math and computer graphics
[1]: https://www.youtube.com/watch?v=I5CTFMuFvb0 [2]: https://www.oculus.com/experiences/rift/1118609381580656/
Maybe the submission title should be s/Blog of/Articles by/, or actually link the blog.
If you like graphics and somehow haven't found it before, check it out!