For example, ENTRANCE TRANSITION resolves a conflict among inner psychic forces.
WEB OF TRANSPORTATION resolves forces that lie partly in the field of human need, and partly in the politics of local agencies.
For example, the old Danish house built in 1685 has certain spatial relationships, such as: a) there are alcoves arround the edges of the main room, b) the alcoves have seats, c) each one is big enough to hold one or two members of the family, d) the alcoves open into the main room.
The forces at work: a) each person has own private hobbies,
b) communal places in the house must be kept tidy,
c) people in the family would like to be together.
The pattern is an attempt to discover some invariant feature that distinguishes good places from bad places with respect to some particular system of forces (constraints). To be alive the pattern must be shared.
Patterns can be shared and used by a small group, such as just two people. (Example: A mother takes TV away from her only son's room and place it in her bedroom. Her bedroom serves as living room and workplace for both of them.)