are you seriose?
that illusion is possible to replicate, puting bricks just like that and the shadow on the slate could be invinsible bricks
if there IS a end to slate, then y the hell is there a edge?
It's just a single brush. It has to be finitely big because you can't model stuff that is infinitely big. Generally interiors do not support alpha and transparency, but you can make invisible walls if you want. The old space station map in AIO used them as windows.
If you want to see the edge for your self, load
the ice palace beta save and follow the road all the way out to the edge.
Actually, if you follow that road to the edge, turn right, and follow the second road, you'll find another edge.