Tetris wall
Dear wife,
I agree to have the decoration you want everywhere in our new home. You can have all the furniture and appliances you want in the kitchen. I’m OK if all the shelves with my computer books are in the basement. OK too if you don’t want to see the file server in the living room. Agreed: I’ll put back Windows on your laptop. But …
But I absolutely want one wall painted like these:
Jean-Etienne 
Photos found on Olybop.info (without original credit). Other walls with Tetris can be found on Flickr.
Why not Tetris-shaped bookshelves?
It could have been nice indeed
But bookshelves are less easily replaced than a wall is repainted (for when I will want a Star Wars or Matrix wall).