I'm entirely failing to envision the process. I want to ask why is the first step (?mapping the book photo to a face of the cube?) is not just restating the original problem, but it's obvious that that question must be missing the point.
Don't let the word "cube" confuse you, a 2D-cube is just a square.
I have the full explanation right here if you're interested: https://wordsandbuttons.online/biwhatever_transformations.ht...