The Hypercube of Fiction is an object containing every fictional Universe (Ones thought of by mortals). It exists on The Ball of The Existence guarded by Cosmic Animals. It is very often used to gaze into a Universe, or even feel how it is to live in it. The Hypercube is usually considered as a Metaverse.
The Hypercube of Fiction packs things as tight as possible. For example, if the only two ideas both consisted of happenings on a single planet, with no description of anything outside of their orbit, they would be in the same Solar System. Because of this, it is unlikely it will every be full. However if it did, one of three things are theorized to happen:
A. The Hypercube would collapse.
B. The Hypercube would grow by expanding itself outwards.
C. The Hypercube, as well as The Ball of The Existence would grow by gaining an extra dimension
These theories are all incorrect, because the Hypercube is infinite. The way this works is because The Third Cog is contained by it.