This is the Piano app.
It consists of only a few audio controls, rectangles and timer control.
In order to reduce the sound source data size due to playback delay in iOS, the sound uses a sine wave rather than a piano sound.
(2018.12.24 added)
I added a recording & playback function in this app.
This function is realized using Collection and Timer control.
movie (from Twitter)
https://twitter.com/KodamaJn/status/1071090977484337152
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