This is metronome program like digital hardware metronome for musicians. Anything superfluous. All best musicians are engaged under a metronome for development or ability maintenance exactly to play up to the mark. A standard scale of rate. As has shown experience of rehearsals, light indication practically is not necessary, as musicians listen to a metronome and in is much more often look at the tool, than on the metronome indicator. Professionals recommend to warm up hands exercises with moderate rate not less than 30 minutes. Only after that the musician presumes exercises on the high-speed technics of game (after a break for rest of hands).