When playing a musical instrument, metronome sound sometimes is drowned out. So the color metronome allows you to follow rhythm by screen glow.
To try out this way please open the link http://cadmy.ru/metronome.html.
You can set the bpm rate by sending a parameter in a URL like http://cadmy.ru/metronome.html/metronome.html?bpm=120.
The default bpm is 80.