This is comparable to the ten sefirot of Atzilut: Although, they are compared to the color white, nothing can be discerned within them, neither a number nor any change, or some similar attribute. Nevertheless, by means of the illumination of the white into the worlds of Beria, Yetzira, and Asiya, which are the three hues of the substance of the letters, all the changes come necessarily from the ten vessels of the sefirot of Atzilut, despite the fact that there are no vessels there with respect to it itself, as it is entirely white. This is like the metaphor of the white in the book, in relation to the letters and their combinations, as its illumination into Beria, Yetzira, and Asiya fashions the vessels within them.