We Belgians are famous for our being able to find ways around a problem... and for evading taxes (no wonder, we pay most of them in the world!).
No rule or there is a way around it, we think. Take Eric Vekeman from Zegelsem (a village in East-Flanders). He was married and his wife had a shop. But the wife died and after a while Eric wanted to transform the space for the shop into a garage. But he did not get a permit, as the buildings in his village are protected.
So Eric began to think how he could solve his problem. He did not like to leave his car outside. So he figured out a way to make a wall turn. You see how it works in the picture underneath;
He put the window on a metal frame and also the brick wall under it. So now he can drive his car into the space, and close up once more. Only problem is he has to do it by hand - he's still thinking about how to motorize the construction.
Pretty clever, eh? And the best part is, nobody can do anything against it, as the front of the house remains the same.