Press the green flag and draw, it only plots points while you press the mouse, the accuracy of the program depends on the amount of points you plotted so if you want it accurate make your drawings slower in order to have more points plotted. Once you're finished drawing press Space and wait for it to calculate. While it is animating you can switch between seeing all the arrows and seeing the dot trace your drawing by pressing Space at any time. You can also change the amount of arrows being used with the left/right arrows on your keyboard. You cannot exceed the amount of arrows it calculated to begin with though. While it is running press 1,2,3 or 4 to show different arrangements I made (4 is the cool S)
Finally applied Fourier Series