"In the towns of Baarle-Nassau (NL) and Baarle-Herzog (BE) you can find dutch enclaves inside Belgian enclaves inside a dutch village. The map looks really wild.In these two towns the border even goes through the middle of the houses and shops.
For this case they created the “front-door” rule, meaning your house belongs to the country your front door is in. In the cases where the border runs right through the front door, the property owners can choose which country they belong to."