Selected diagrams from “Secret Symbols of the Rosicrucians (Part I)” by Franz Hartmann (1888). From an edition by “Celephais Press”. See also: “Part II”. For more on occult symbolism, please visit “Noise vs. Signal”.
What are Binaural Beats? Tones produced specifically for the purpose of altering your brainwave frequencies. The posts in the link also contains an exclusive free binaural beats sample of a pure alpha wave.