Hello Oscillator

We're introducing new concepts here, so the javascript hasn't changed all that much since Lesson 05

Choose a waveform

Make sure your volume is up

Play these black or white keys on your computer keyboard
(not designed for mobile devices or touch screens)

keyboard layout

You may wish to see what these oscillations "look" like

sine, square, triangle and sawtooth waveforms

Now take a moment to learn a bit more about sound:
(Note: Old-School Youtube, at some point, suppressed pure sine waves, so you won't hear them, here —too bad! But it's just a couple spots.
Find me a more complete and friendly introduction to the topic, and I'll substitute it here