Christopher Alexander’s design patterns for architecture are above the domain level of the pattern language described on this site. A brief description of those that are supported by this pattern language are given below. They are designated as ‘Axxx’ to help refer to them, where xxx is Alexander’s pattern number.

A240: Half-Inch Trim

A free and natural building will contain minor variations and tolerance in materials, unlike a ‘totalitarian, machine building’, that requires finishing.

Alexander argues that trim is not just ornamentation, but an essential part of the building process that is needed to absorb tolerances between pieces of material. In addition, there is a psychological reason for keeping trim on the order of half an inch: the perception that it belongs to part of the building’s hierarchy. Natural surroundings contain a range of detail from molecular to landscape. There are results in cognitive psychology (reference??) that show that jumps in scale must be in the range of 1:5 to 1:10 to be perceived as part of a natural hierarchy.

Since most materials have a fibrous or crystal structure with detail on the order of 1/20″, the smallest building details should be on the order of 10x larger to bridge the perceived hierarchy (ie, ~1/2″).
Therefore,

Whenever two materials meet, some of the trim components should be on the order of 1/2″ wide.

This pattern can be supported by Ornament (A249) and Warm Colors (A250).

A249: Ornament

It is instinctual to decorate our surroundings.

From Alexander: “The main purpose of ornament in the environment- in buildings, rooms, and public spaces- is to make the world more whole by knitting it together…” At a large scale, things such as properly designed entrance transitions tie boundaries into a united whole. At small scales, the grain of stone or wood can tie together a material. The intermediate scale (the ‘human’ scale that is the domain of our pattern language) requires ornament to fill the gap and tie things together into a whole.
Therefore,

Use repetition of simple themes to bind together edges and transition in the building.

A250: Warm Colors

The warmth of colors in a room can add comfort, unlike cool colors that can be depressing.

Red, orange, yellow, and brown are considered warm colors; blue and grey are considered cool colors. It is the color of the light in the room, not the necessarily the things in it, that makes a room feel comfortable. Consider, for example, the difference between candlelight and overhead industrial fluorescent lighting. The color of the light is also influenced by the surfaces that scatter light.
Therefore,

Choose surface colors that work with the available lighting to create warm light in the room.

A252: Pools of Light

Uniform illumination destroys the social nature of space, making people feel unbounded.

Natural lighting is seldom even, usually containing dappled light that varies from minute to minute and across a space. We tend to create social spaces that are partly defined by the boundaries of light, so uniform illumination makes it more difficult to form a natural group. If a group can be contained within a ‘pool’ of light, the cohesiveness of the group is enhanced.

Small bright light sources also distract less than large, less bright areas (Hopkinson and Longmore)- good for local lighting over a work area.
Therefore,

Place lights to form pools of light to reinforce the social character of a space, making sure to keep darker spaces in between.

A253: Things from Your Life

In attempts to please others, we sometimes forget our instinct to keep things around us that have meaning to us.

Interior Design can be taken too far- people are sometimes left feeling they will spoil the design by adding any personal touch.
Therefore,

Decor is most beautiful when it comes straight from your life and contains the things you care for.