The symbol I use for my music is a Hexagon with three short sides and three long sides. It's nicknamed the Triaxagon... and this ancient shape is crucial in the lore of the universe K-23.
The Kidrat are inter-dimensional nomads who placed the Triaxagons across every universe they have visited, and serve as eternal gateways to these other universes... including the one you're in now... Triaxagons also produce a mesmerizing sound. much like the ones I will create for you.