A pattern language - Chris Alexander’s original - is a language of evolving of both the spatial organisation of built environment, and the experience of inhabiting it.

It ranges from

• the order of a region, and relationships of an urban area to surrounding ‘countryside’,
• through to the order of a neighbourhood, street, dwelling or room; and
• to the hands-on, in situ construction of a building organised on these lines.

See Christopher Alexander, Sara Ishikawa & Murray Silverstein (1977), A pattern language - Towns, buildings, construction, Oxford University Press. [http://library.uniteddiversity.coop/Ecological_Building/A_Pattern_Language.pdf pdf].

It ranges from Pattern #1 Independent regions ("Within each region, work toward those regional policies which will protect the land and mark the limits of the cities") and related patterns including #2 The distribution of towns and #3 City-country fingers; to . . #140 Private terrace on the street and #145 Bulk storage, #159 Light on two sides of every room, #180 Window place and #203 Child caves.

There are 204 patterns in the ‘design’ sections of this language, and a further 49 in the ‘build’ section.