You could make a tile in your tileset to do it, like dataflashsabot said, but an actual object would be more effective. Also, using a tile isn't really practical since you only get a certain amount and you'd end up using a lot of tiles if you had a lot of these situations, plus it'd still be solid to Juni, even if you could get by it; it'd be sorta odd sticking out. But! It is really the only workaround, other than just changing the screen a bit.