We are now waiting for Santa to arrive. :D
![22 terraria houses without background wall](https://i.imgur.com/T3khN68.jpg)
on reddit
UPDATE (july 2018): these kind of houses will NOT make npcs spawn and already spawned npcs will not move in these houses on their own (if their original house is destroyed for example). I guess that is one way how they patched the 'infinite house'