Canvas (As a setting)

Canvas starts as Earth, as it is on August 19th, 2018 C.E., at 10:09 PM.
Canvas is fictional. Fiction is a construct of perception. It is a lie we tell to speak about truth.
Canvas is formed from written texts, and unwritten thoughts. By reading this passage, and thinking about the concepts it presents, you are creating more of Canvas.
Canvas is the neutral point by which the fantastic is judged. Reality as we know and understand it, so one can juxtapose the worlds we visit through story and song against our own.
Canvas sits just left of center of the Medium, the endless expanse of all Settings of fiction.
Canvas is, in its natural state, mundane, as consistent and probable as our own world appears to be.
It is not in its natural state.
As of now, right now, this world is beset on all sides by scraps of stories and worlds that were never written, never started, never finished, never spoken, never told, never published, and never fully realized. Endless narrative potential, begging, pleading, DEMANDING to be made real; forcing itself on a world that was never meant to hold it.

Geography

Canvas is as much of our world as it can be; mostly damp, sometimes dry. The deepest depths of its seas are unwritten, and the highest heights of its skies unseen. It is ever expanding, inward and outward; filling in wherever the stories that are told upon it demand. Imagine if you will, a procedurally generating world in any game; only ever rendering what is being observed by its audiences, and the little pawns that call themselves people that live in it.
It is as large or small as the plot demands, it could be the vast infinities of the cosmos, the entirety of Kazakhstan, or even a small bar in Boston, where everyone knows your name.

Fauna & Flora

As above, so below. The plants and animals native to Canvas are about the same as they are in "real" life, right down to your neighbors, their pets, and even you. Anything not currently relevant to the plots in focus could be considered to not exist, and yet, the biosphere marches on no worse for wear. Life finds a way, even when by all accounts it really shouldn't, given the lack of narratively important biodiversity.
The one species that can be guaranteed to be in focus, are the Homo Sapiens Sapiens; the modern human. You know what those look like, don't you? Skin, eyes, maybe a mouth, 0-4 limbs, a hardened skull to protect a squishy brain? Who else could write about humanity, to feature in stories about humans, than themselves. Much like how Canvas is the gauge by which other worlds are judged, humans are the metric by which other animals are measured. When a creature is uniquely clever, we say that has human-like intelligence after all.

Alternative Name(s)

An Unwritten Rule, An Unspoken Truth, An Unbroken Promise

Type

Planet