One of the simplest Visualizers ever, made by me. Instructions: It only works if you click Allow. I played background music and it worked. Just click the green flag and enjoy. Only 2 scripts required, the third is optional (color change). You can adjust the 10 in the yset to make it go higher or lower. You can adjust the 10 in the xchange to adjust the difference between length of the wave (slower/longer). You can adjust the PenChange to adjust the color.
None, just thank the backround music you use.