Crowley thought that each soul was a mode of the absolute first principle, Nothingness. A soul is to nothingness as a particular shape is to space. It is a limitation. And just as an enclosed area makes conspicuous not only the area inside the enclosure but the rest of the space without, so does the self-limitation of nothingness bring into relief not only the particular soul (Hadit) but the rest of the Ain Soph (Nuit) in which the limitation occurred. This is how the self-cancelation of Ain grounds both Nuit and Hadit.
You can draw an infinite number of shapes in space. The total space would serve as a coordinate system. Likewise there are infinite ways Ain limits itself to create souls, and the space-like way in which the different particular nothingnesses (Hadits) are related to one another is Ain Soph Aur. I think that’s the idea Crowley came to with the Star-Sponge vision.
The self-limitation of Ain/nothingness creates determinate nothingnesses or souls (Hadits/stars). This simultaneously creates Ain Soph (Nuit). The purely conceptual/mathematical relationships obtaining between the stars in Nuit is Ain Soph Aur. Together this system forms a noumenal sum total of reality.
When a particular soul incarnates, it interprets these purely noumenal relationships phenomenally by means of the forms of space and time. This transforms space-like relationships into actual spatiotemporal relations.
The soul has latent within itself something like a computer program that contains all the information about itself and its relationships with all the other souls in Ain Soph. Incarnation is like running that program. Space-time is like a graphical user interface that allows the soul to interact with the program within itself. If it weren’t using that interface, all the information within itself would remain latent, which in the case of a soul would be an absence of knowledge about itself and the universe.