Dirki, Emmanuel, Maker:

Here's my way of doing it. I once posted this solution here, but couldn't find it again. Strange thing is, that for some reason it doesn't work the way it should. Instead of following the space I draw, the floor also fills the middle part. As far as I am concerned, this is an "unwanted feature".

The problem with "stacking" floors is that they cause strange behaviour in the rendering window.

Hans