Generates a beep sound with specified frequency, duration, and volume.
beep(frequency, time, volume)
Generate a beep with the default parameters (440 Hz, 200 ms, 100 volume)
beep();
Generate a beep with 1000 Hz, 500 ms, and 80 volume
beep(1000, 500, 80);
Generate a beep with 500 Hz, 1000 ms, and 50 volume
beep(500, 1000, 50);