What does the vast material universe look like according to Vedic Cosmology, which exists in 1/4 of the spiritual sky (of all that there is)?

Garbhodakashayi Visnu seen in painting below, has His own "secondary universe" that exists deep inside each massive Brahmanda universe (universal egg or shell) that originates from the Body of Maha-Visnu, from the pores on His skin and via His breathing.

Garbhodakashayi Visnu is an expansion of Maha-Visnu, who is an expansion of Balarama, who is Krsna's first expansion. 

In this way Garbhodakashayi Visnu has His own material universe deep inside each of the Brahmanda universal shells created by Maha-Visnu  

There are billions of Brahmanda universes and inside each one is a secondary universe each with their own Garbhodakashayi Visnu and Brahma.

This means there are billions of Garbhodakashayi Visnus, Brahmas and demigods, but there is only one Maha-Visnu, who creates all the impermanent decaying material universes (Brahmandas) where the jiva-souls experience repeated birth and death. 

The material creation is 1/4 of the spiritual sky where everything is temporary and experienced through the movement of material time (past, present and future)

Vaikuntha and Goloka Vrindavana on the other hand, make up 3/4 of the permanent spiritual sky that is permanent and situated in the "eternal presence" beyond movement of material time's past, present and future.

The spiritual worlds of Goloka-Vrindavana and Vaikuntha never experience impermanence or decay, or repeated birth and death like those jiva-souls in the material creation do.

In Vaikuntha and Goloka-Vrindavana the jiva-souls live eternally as a bodily form of their choice within the "eternal presence" of Krsna Consciousness.*.