1.) First, shift+click the green flag to turn on Turbo Mode, then click the green flag normally to start. 2.) Select the number of edge points you would like to define for your fractal using the slider on the top left. Three points will produce the cleanest fractal (I recommend you start there), but you can experiment with other numbers! 3.) Hit the spacebar ONCE to lock in the number of edge points you would like for your fractal. 4.) Then, once for each edge point, move your mouse to wherever you would like them to be and hit the spacebar once. Larger distances between points tend to produce more detailed fractals. To restart from the beginning, just click the green flag again. Also, once your fractal is being drawn, try different color settings for the slider on the top right - you can make some nice patterns!
The inspiration came from a Numberphile video - go to https://www.youtube.com/watch?v=kbKtFN71Lfs to see the math behind the fractals. (It's actually really simple!)