In the theory of Tone and Color Alchemy, we have observed the fundamental Alchemical Proportion
SPEECH : SIGHT :: TONE : COLOR
as a revelation on the text of The Book of Tokens Meditation on Heh: "In very truth, I utter myself by seeing."
The mystery of the Heart is in the hidden connection between all things. There must be a direct connection or common ground to both speech and sight, or tone and color. What is it?
This is really the core mystery of the Sepher Yetzirah. The text, as brief as it is, contains the basic pattern of the Qabalistic model. This is spelled out quite explicitly in the very first verse:
With 32 mystical paths of Wisdom
And He created His universe
with three books (Sepharim),
with text (Sepher)
with number (Sephar)
and with communication (Sippur).
The Sepher (text) refers to the form and shape of the Hebrew Letters. We use our SIGHT to differentiate the letters from each other.
The Sippur (communication) refers to the letters as spoken utterances: SPEECH.
The Sephar (NUMBER) stands between the two and unites these two different aspects. How? Through RHYTHM! Just consider how the whole Marcotone method is based on how the frequency (RHYTHM) of specific sound waves (tones) has an exact numerical correspondence with the frequency (RHYTHM) of specific light waves (colors).
There is a Gold-mine (yours and mine) of wisdom that can be revealed through contemplating NUMBER as that which unites TONE and COLOR. I have acquired much already from only surface exploration and observation. I will continue to dig deeper. Those who are interested in this topic would find the following clues as good bait for the Fish-Hook:
Arithmetic = a-RHYTHM-etic