I don't know, Lisa, the towers are so tall in 319, if they are cake I wonder how they support themselves? They almost have to be something else, maybe pvc pipe, although that would make the whole cake very heavy...more than likely the cardboard tubes you'd use for mailing posters, etc.
I love the ones with the stairs, how would you make those? The most obvious answer would be fondant, but it would intimidate me some to try to attach them to the cake! Janice