HTML is really naff for writing maths, though
things have improved recently. You can get an idea of what I write
about on my scribblings page or my publications list.
Here are some fractal anims. Fractals are nice, 'cos they're so easy to play with. In secondary school I wrote myself a progam for drawing pretty pictures, and then strung them together.
Originally you need something like xanim to show them, but I've been able to regenerate some of these and upload them to Google Plus. The original links aren't really quicktime movies, but they are of a format xanim knows (Amiga IFF). If anyone can tell me how to convert them into something more net standard let me know. The images for some of these made it into a talk I gave in Maynooth in November 2000.