This is just like the website chrome music lab. This is still a WIP Follow me for updates! History: V1,0,0: the basics are made. V1.2.0: the colors change and the full scale is there. V1.4.0: you can unclick and click the buttons. V1.4.4:When you click the same note it doesn't make the annoying echo noise.
Credit to musiclab.chromeexperiments.com for the idea.
