How to play. The disk chants a sequence of runes — each glows and sings its own vibrating tone. When it finishes, repeat the order by tapping (or pressing keys 1–6). Every round the chant grows by one rune.
Why it trains memory. Each rune is anchored four ways at once — its shape, its place on the disk, its colour, and its tone. Working memory holds more when you chunk the chant into small groups and lean on the melody to carry the pattern. Hum it. Picture the runes lighting in turn. The tones do half the remembering for you.