I made it stackable by making the lid/hood exactly the same as the bottom of each viv. So the bottom of each viv can function as the lid of the one below it. I have one lid (that will fit all vivs) to go on the top viv, so I can also decide to change the vivs around at some point if I wanted to. The lights of the vivs are not mounted onto the hood but onto the vivs themselves, so it doesn't mess with the lights and wiring if or when it's being changed around.
No I haven't finished the third one yet (haven't even started on it... :roll: ) because I'm moving in a week and a half and I rather build it there than having to move it. (It's already going to be a challenge moving these two... :lol: ) I'm actually also playing with the idea of making the third one a two story one that would fit next to it instead of on top of it, so that the whole thing would be wider instead of taller.