Draw on the screen with your mouse Press SPACE when done Wait while it calculates the Direct Fourier Transform function Then it will calculates the Direct Fourier Transform of itself and repeat up to 5 times Then it will start drawing the Direct Fourier Transform of each previous DFT on the screen until it gets to the last one.
Note if the processing time goes up that means the Direct Fourier Transform is getting more complex (good thing) if it doesn’t it probably is draw 10 pixel large drawings which is boring.