Use the sliders to change the sine wave's properties you may have to use fullscreen to reach the rainbow mode. Watch the sine wave & experiment with different options to make different sine waves. You have to wait for the sine wave to create the first line before you can change the variables.
If you find any interesting sine waves, feel free to post your variables in the comments, or see inside and change the code to make it start with your variables, then remix. If you have ideas for new variables, please submit them in the comments, or remix and add them yourself.