The challenge was to programmatically draw a Fibonacci spiral. In high school I had tried on a TI-8x calculator after getting it to display the numerical sequence in a loop, but gave up the challenge until diving into ActionScript.

Directions

Click the top-right button to add a square. Each time you click it represents n+1 in the sequence: 1, 1, 2, 3, 5, 8, 13, etc...

Eventually, it breaks. Before then, you can use Flash's "zoom in" feature to zoom into the spiral you have created. Click the top-left button to reset.