click on the image to enlarge.
I have always liked Tromp L'oeil. It serves to change a space which usually needs changing without actually changing it...so there are extra windows on Hampton Court to balance the rooms when in fact, no such window exists. The ancient Romans liked to decorate their rooms with "Tromp L'oeil" because they were often windowless, with only a little light coming in by skylight or oil lamp, but the rooms feel open and spacious with gardens and architectural details that never existed in real life.
Because it was a make belief world, they would have masks, fauns, gods, and all manner of beasts painted on the grotto like walls, giving the name "grotesque" to this art form.
I'll see if I can find some more examples.
Have a good week, and I hope I have made you smile this morning!