Set und Ketten-Gebäude
Set Buildings are special buildings, which are placed next to each other in order to give additional bonuses.
There a various building sets in the game.
How do building sets work?
Each set building has a bonus on it's own. Being placed next to other set buildings of their kind, additional bonuses per building are added.
It's important, that the buildings of the same set are adjacent to each other. Combining set buildings of the 
Indian Palace Set with the 
Indian Fountain Set will not grant additional bonuses.
Example:
In order to get the bonus for 3 buidings for different buildings of the same set need to adjacent to each other.
Wrong:
3 set buildings are directly connected to the Maharaja's Palace, but only 2 of them are from the Indian Palace Set. The third one is from another set, the Indian Fountain Set. Therefore the bonus is only granted for 2 buildings.
Correct:
3 other, different set buildings of the same set, the Indian Palace Set are adjacent to the Maharaja's Palace. Therefore the bonus for 3 additional buildings was granted.
In order to know, which buildings belongs to which set, just look up the details of the building in the inventory or in the city. It is either directly mentioned to which set they belong, or marked with the building set icon, which is unique to each set.
The icons of the current sets are:
Indian Palace Set
Indian Fountain Set
Cherry Garden Set
Winter Village Set
Royal Garden Set
Things to keep in mind:
- The bonus is only granted, if buildings of the same set are placed next to each other
- The bonus is only granted, if different buildings of the same set are placed next to each other
- The bonus is only granted, if each building is adjacent to the other set buildings
- If the set buildings are torn apart, the timer of those buildings will be reset (not if moved in Reconstruction Mode)