Experiment. Visualize. Click to place points. Spawn another Bézier curve with the space bar.
You're probably wondering what a Bézier curve is. It's a cool thing that you should research. Basically, there are 2 lines. They each have the same amount of points at equal intervals. They connect to their opposites, creating a curve shape. The black dots that make the curve are actually placed at increasing intervals along the colored lines. The 1st one is placed at an interval of "n" along the 1st line. The 2nd one is placed at an interval of 2n along the 2nd line. Etc, until at the end you connect all the dots and get a super nice looking curve!