Patatap is a visual sound kit application with animations by computer programmer Jono Brandel and Japanese electronic duo Lullatone, consisting of Shawn James Seymour and Yoshimi Tomida.
I have made a similar website which functions almost the same way.
By pressing different charcters in keyboard, it generates a unique animation and sound effect.
I have used Paper.js library for creating animations and Howler.js library for creating sound effects.