Have you ever thought why oscilloscopes tend to look something like this:

If I'd ask, what is the frequency range of this waveform? Would you have an answer or able to make any guesses without looking at the source code / midi inputs?
And what about this, is it exactly twice the frequency of the above?

or this?

You see the problem: you can't tell the frequency of the waveform because the period information is not available - ie: the time interval which one oscillation completes.
But wait - there is more that's missing: what if there is a second waveform that is played at double/half the frequency, how could you tell just by looking?
Generally, you can’t.
There are two main problems presented by a traditional oscilloscope plotted in:
It would be nice if I can recognize these just by looking at the graph visually:
In fact, there are already two very compelling solutions to these, which are: