A simple 0.2s musical keyboard

[@comphert]

For those who want to try on phone
0:02 0:04 0:06 0:08 0:10
1(5) 2(6) 3(7) 4(1) 5(2)
6(3) 7(#4) 1(5) b7(4) 0
0:12 0:14 0:16 0:18 0:00
Well, 0:00 seems not working, you may have to slide the progress bar to the leftmost to accomplish this.