One cool way to use this would be(make sure you have microphone access) unplug any headphones, and play a song so the mic can hear it and it will visualize the song in the form of a sound wave. Blast Processing is preloaded inside so to play that song, press the 0 key. To stop the song, press down arrow key. Its a simple script but makes very cool effects. And you can play any sound that it will do. I saw another audio visualizer on Scratch that was coded to visualize only one song, but this one goes by the loudness so it will visualize any sound.
All art is by me and by the pen which made the sound wave, which I coded. Yeah ill stop there... Hope you enjoy!
