WebAudio sound is suspended until you click anywhere on the window or press a key on the computer keyboard.
This program is designed for full screen mode, press F11.
Doubleclick the LFO Rate button to change the waveform from triangle to square and back.
Press F1 or click the phone volume button to open the Menu.
Menu shortcuts: CTRL-A, CTRL-O, CTRL-S.
Press F2 to show this window.