This page was very useful when I was teaching a (particularly clever) 12 year old kid about complex numbers. He really wanted to render Mandelbrot/Julia fractal

This page was very useful when I was teaching a (particularly clever) 12 year old kid about complex numbers. He really wanted to render Mandelbrot/Julia fractals (using Processing), had done some googling on the subject of complex numbers, but most of the articles he found were ever-so-slightly above the level of math he had learned in school (turned out he hadn't yet learned about the distributive rule for multiplication, that (a+b)*(c+d) = ac + ad + bc + bd, which is kinda important if you want to work out (x + iy)^2 given that i^2 = -1). I was lucky that someone explained me complex numbers when I was 15 (I also had wanted to plot Mandelbrot fractals for a long time, but back then I didn't even have the Internet to help me), using a very visual approach similar to the featured article. That is, multiplication by -1 is the same as a 180 degree rotation around the zero ... so what would happen if we decided we could rotate by 90 degrees? So I took a similar approach. Then I remembered this article about "folding Julia fractals", the visualizations in this article were a great supplement to the graphs and scribbles we made on paper, exploring the weird world of complex numbers. I did a little video interview with him to show off his work (cause, you know, I was kinda proud): https://www.youtube.com/watch?v=rR6klRdtjsg https://www.youtube.com/watch?v=rR6klRdtjsg -- It's in Dutch and I'm not a very good interviewer, also no editing (and yes I should've held my phone horizontally, sorry). But the best part was two weeks later, I kinda feared I had dumped too much information onto him at once (especially given I also had to explain the distributive rule), I asked him if he had made any improvements or additions; "Yeah, I had to wait at the dentist's this week, and I had Processing for Android (APDE) on my phone, so I wrote the Julia version of the Mandelbrot zoomer" ... Oh, if only I had have a powerful pocket computer when I was 12!!! (so jealous!)