Tempo can be thought of as a source of the musical pulse.
Meters divide that pulse into measures and beats.
- Tempo pulses be divided so they can be sympathetic to the meter.
+ Tempo pulses can be divided to be in sympathy with the meter, but this does not affect the beat
+ at any particular time.
Note that Tempo::beats_per_minute() has nothing to do with musical beats.
It should rather be thought of as tempo note divisions per minute.