Surrealistic Room

Idea- I am thinking of doing a project where what looks like a box with some sort of outdoor kind of thing inside it inside of it.  
Specs- I am going to be doing it in Photoshop in a 3000px by 3000px document.
Research-  I found a tutorial for this where is look like a boat on water and and the sky has the corners of a box.  I am excited to get started on this.  After the tutorial i hope to make one of my own with different components but keeping the same idea of it being inside a box.

I am having a little trouble with the tutorial.  There are many different kinds of brushes that needed to be used to put waves in the corners and i had lots of trouble getting these brushes.  The tutorial did not turn out as well as i hoped it would cause i also could not find some of the pictures i needed and finding similar ones was difficult too.  The tutorial came out pretty good and i figured out a way to make the sides look less hard on the other room i am making

 Comps-

So for the room that i made i found a background picture of trees and it had a path in it and decided that it would look good with the water flowing out from it.  I also used the clone stamp and put the on the edge to make it look a little better and not as hard and ridged.