Solid Rooms, experiments with Dynamo / 02

I made interesting evolutions after my room experiments with Dynamo.
If I insert a column or an other closed room inside my original room, is possible to extrude the 2 boundaries lines and make a solid difference.

Here you can see the general map

From the LunchBox Room Element Collector is possible deconstruct the Boundaries list with the List.Deconstruct Node. In this way we will have a list for each room. 

Now we can extrude the two closed boundaries 

At the end is possible to make a solid difference