Hi everyone, firstly i would like to explain why i came up with a new idea on adjacency bonus for districts. Right now, developing city building quarters is very fun at the beginning but when adjacency bonuses start to kick in, quarters are just meant to be placed next to the same ones, usually resulting in a boring carpet of the same quarter.

The system I’m going to explain tries to assess this problem and to include all possible districts into city development, also taking into consideration the actual meaning that district names carry with themselves.

For starting, district (or quarters) will be divide in three macro-categories: Productive Quarters, Residential Quarters and Service Quarters (see the picture below).

Productive Quarters are the places were all goods are made or gathered. This are also the places were «Farmers» (as in people who live in Farmers quarters) and «Makers» do work, and the more workers live near them the higher will be  their usefulness. Therfore, they provide adjacency bonuses to Residential Quarter. 

1. Artisans Quarters thematically related to Farmers (Salt, Sage, Coffee, Tea, Saffron, Dye, Silk, Incense, Papyrus), Horse Ranches and Harbors will provide + 5 Food to each adjacent Farmers Quarter (+7 if Luxury Manufactory). 
2. Artisans Quarters thematically related to Makers (Ebony, Obsidian, Porcelain, Gold, Gemstone, Lead, Mercury, Silver, Weapons) and all the Mines (Copper, Iron, Saltpetre, Coal, Oil, Aluminum, Uranium) will provide + 5 Industry to each adjacent Makers Quarter (+7 if Luxury Manufactory). 

1. In Farmers Quarters find home not only farmers but also ranchers and fishermen. 
2. In Makers Quarters we found woodcutters, stonecutters, miners and all the other artisans.
3. Citizens Quarter will be a new district that at some point will be unlocked in the tech tree. Here lives the people wo do not work the land or produce goods, but do some other various jobs inside the city. The district does not exploit any resource but provide higher adjacency bonuses to Service Districts.

Service Quarters provide services to the people living in the city, therefore they will be more useful the more people live around them and so they get adjacency bonuses from Residential Quarters.

1. Market Quarters are the places where commerce happens, people buy and exchange food, goods and of course money. It does not have to be adjacent to resources, as resources are brought to the market to be sold to the people. Given the basic effects of the market quarter, it provides additional +1/+2/+3 gold for each luxury resource (depending on the luxury gold values) extracted in the city territories plus +2 gold for each Residential Quarter adjacent to it (+4 gold if Citizen Quarter).
2. Research Quarter is not only the place for scientific discoveries, but also were people get instructed. Therefore the more people live nearby them, the more science they can produce. It gets +2 science for each Residential Quarter adjacent to it (+4 science if Citizen Quarter).
3. Common Quarters are the places for cultural enrichment and entertainement. They need to be close to where people live to carry out their role. They get +2 influence and +5 stability for each Residential Quarter adjacent to them (+4 influence and +10 stability if Citizen Quarter).