Hi VeroniQ
Glad you liked it
The levels between the main floors have on them various walls, for instance, level 7 has walls which form the risers for the middle section of stairs, they are roughly triangular, but to avoid using 2 boxes and a triangle, which would not texture evenly, i prefer to use a wall, also these levels have the floor depth set to 1 mm so the minimum wall height does not include a floor depth. [:)]

Mike