The door concept!

Alright, so after sketching some ideas in black and white, I decided to run some of the thumbnails from the previous post through ArtBreeder to further explore ideas.  

Since there is no such thing as a 'door' gene in ArtBreeder, what I ended up with was a bit too abstract, but using the architecture base I got some pretty cool suggestions. To be fair the first few results were not the best:

I kind of like the first one and third one for a more surreal piece... something like a portal into a different dimension could be fun. However, ended up using the fourth option that looks like the wing of a moth: