The optional cues carry no instruction, answer, score or success signal.
They are low-level mono sounds. Never rely on them to communicate a required
step. Show, sign or say the same information, or omit the cue entirely.
One soft, lower rounded tone that fades away. Total length about 0.45 seconds.
Hold up an open hand or say, “We can pause now.”
The sounds are original mathematical sine waves with a short harmonic, gentle
fade in/out and silence padding. They are not copied from a recording or
music library. Playback volume still depends on the device; begin quietly,
keep the speaker away from the ear, and honour a child who prefers no sound.