Sierpinski
A javascript Sierpinski fractal demo, just for fun!
Try it out here: http://mrtimuk.github.io/sierpinski/
Tick some checkboxes to form the seed pattern that you want, then click the + and - buttons to draw the fractal.
Notes
This uses a Canvas if your browser supports it, otherwise it'll use SVG (which is quite resource-hungry). You probably don't want more to draw more than 7 iterations in any case.