Trying to play notes on two piezo buzzers

I'm working on a project where I have two piezo buzzers:

Looking at this example:

It says that I can only play one at a time. How can I play two at once?

Also, two more questions:

  1. Should I be running the buzzers on analog pins or PWM pins?
  2. Are these functions blocking or non-blocking?

CuddlyKittens11:
It says that I can only play one at a time.

I don't read it that way: I read it that it does it that way, but doesn't have to do it that way.
Having the delay the same as the the tone's duration means that the next tone only kicks in when the previous tone completes; that's when the delay() expires.
So I reckon the tone isn't blocking, but the delay of course, is.

edit.... above is nonsense: the tone ref page says

Only one tone can be generated at a time. If a tone is already playing on a different pin, the call to tone() will have no effect.

.....hence the delay in the example, to let each tone complete before the next.

CuddlyKittens11:
Should I be running the buzzers on analog pins or PWM pins?

PWM pins. Analog pins, if not redefined as digital pins, are for reading analog inputs.

Can run them on digital pins too, all done blink-without-delay style.
In this thread I demo'd I have code for 13 tones, and demo'd 8 running at once (ran out of buttons to show all 13 at once).
http://forum.arduino.cc/index.php?topic=179761.0

In just amended my first post since the ref page for tone() says:

Only one tone can be generated at a time. If a tone is already playing on a different pin, the call to tone() will have no effect.

But CR, sounds like you do play more than one at a time, with blink without delay style coding?

Yes - I posted a video showing 8 notes at once, and the code was written to do 13.
Tone library not used at all.

CrossRoads:
Tone library not used at all.

If using tone(), does it need a PWM pin or is any digital pin ok? The ref page "sort of" implies PWM, it reads PWM-like:

Generates a square wave of the specified frequency (and 50% duty cycle) on a pin.