As the articles in interactions continue to focus Interaction and system designers alike gravitate to the idea of pattern languages. The notion of patterns comes from the work of architect Christopher Alexander, who with his associates Sara Ishikawa and Murray Silverstein of the Center for Environmental Structure, published A Pattern Language in 1977. The book defines a set of fundamentals for building and planning urban and architectural projects that can be used by non-expert designers. “Each pattern describes a problem which occurs over and over again in our environment,” wrote Alexander and his coauthors, “and then describes the core of the solution to that problem, in such a way that you can use this solution a million times over, without ever doing it the same way twice.” While the authors addressed architectural and urban problems - in effect, spatial problems - the approach offered (and continues to offer) ready parallels with the design problems faced by designers of all kinds…