Change the sliders on top to change settings, then click Green Flag to render! This is drawing the famous Mandelbrot fractal, which you can read about here: https://en.wikipedia.org/wiki/Mandelbrot_set USE TURBO MODE FOR BEST RESULTS
ITERATIONS controls the number of iterations to use for the calculations. SCALE controls how much to zoom in. Pos X and Pos Y control which part of the fractal to look at.
