This Way Up by Tom Percival

Everyone knows which way 'UP' is. It's the opposite of 'DOWN'.
Or at least, that's what Queetle had always thought . . .

Now, he's about to discover that 'UP' might not be as simple as it seems.
When he meets Meeple, a creature who lives and walks around SIDEWAYS on a different side of their shared planet, Queetle is forced to reconsider everything he thought he knew.

A powerful, warm-hearted picture book from the creator of the bestselling Big Bright Feelings series, celebrating the life-changing power of seeing the world from other points of view.