Problem
The mosaic of subcultures requires that hundreds of different cultures live, in their own way, at full intensity, next door to one another. But subcultures have their own ecology. They can only live at full intensity, unhampered by their neighbors, if they are physically separated by physical boundaries.
Solution
Separate neighboring subcultures with a swath of land at least 200 feet wide. Let this boundary be natural—wilderness, farmland, water—or man-made—railroads, major roads, parks, schools, some housing. Along the seam between two subcultures, build meeting places, share functions, touching each community.
Related Patterns
… the Mosaic of Subcultures (8) and its individual subcultures, whether they are a Community of 7000 (12) or an Identifiable Neighborhood (14), need to be completed by boundaries. In fact, the mere creation of the boundary areas, according to this pattern, will begin to give life to the subcultures between the boundaries, by giving them a chance to be themselves.
Natural boundaries can be things like The Countryside (7), Sacred Sites (24), Access to Water (25), Pools and Streams (64), Still Water (71). Artificial boundaries can include Ring Roads (17), Parallel Roads (23), Work Community (41), Industrial Ribbon (42), Teenage Society (84), Shielded Parking (97). The interior organisation of the subculture boundary should follow two broad principles. It should concentrate the various land uses to form functional clusters around activity — Activity Nodes (30), Work Community (41). And the boundary should be accessible to both the neighboring communities, so that it is a meeting ground for them. — Eccentric Nucleus (28).
Alexander, Christopher. A Pattern Language: Towns, Buildings, Construction. Oxford University Press, 1977, p. 75