kitchens; efficiency apartment
kitchens; …all industrial sites
larger than two acres; a 2x4…
residential areas with 40 percent
of their population under 25
and median incomes between
$6,000 and $8,000; garden paths;
cobblestone paths; a doorknob;
any freeway; freeway exit ramps;
bookshelves [ 6].” Any of these
patterns provides a solution to
a problem that exists in space,
whether the demographics of
a neighborhood, the kind of
structure required for a house, a
transportation issue, or the optimal setup of a dormitory.
As an example, the Pattern
Manual describes the difficulty
of reading house numbers from
a moving vehicle. It states the
context tersely and specifically:
“Freestanding house on a street
where cars move at speeds
between 5 miles per hour and 30
miles per hour [ 6].” The problem
statement is much longer—in
this case, three pages—and sets
out the series of issues the pattern will need to address, beginning with: “House numbers are
very hard to see from moving
cars, especially for the driver.
Many signs are parallel to the
road (on the house face, or garden gate), so that they can’t be
seen from up the street [ 6].” The
rest of the problem statement
includes facts about house numbers and signage, references to
studies on driver vision, and the
limits of potential positioning of
signs—in essence, the evidence
for a case to support the problem. The following pattern, for
instance, addresses the house-number problem:
• Two house signs, each at
about 45 degrees to the street,
facing up and down the street,
respectively.
• If the house is one of a regular sequence of houses all using
this pattern, then the sign letters
are at least 6 inches high.
• If the house is isolated, or
is one of a regular sequence of
houses not using this pattern,
then the sign letters are at least
12 inches high [ 6].
Consequently, a simple pattern that addresses angle and
direction of signage and the
size of letters tackles a broader
design problem. It notes different
use cases—sequences of similar
houses versus isolated or nonse-quenced houses—and offers different variables for the solutions.
While a designer could simply
use the pattern, the richness of
the framework lies in the overall
problem statement and context.
Furthermore, the goal of pattern libraries is not only to offer
solutions to design problems,
but also to solicit critique and
invite improvement. “We want
our ideas to improve under public scrutiny,” wrote Alexander’s
team, “and we want our good
ideas to be potentially combined with other good ideas [ 6].”
The Center for Environmental
Structure first sought to publish
its patterns under the rubric of
a catalog to which anyone could
submit patterns using the format described in this article. An
editorial board would select patterns; catalog subscribers would
receive the patterns. Alexander
and his colleagues thought that
by 1970, patterns could be stored
in a computer and offered to
subscribers—a central feature to
contemporary pattern libraries
for games, object-oriented programming, or Web design [ 9].
Through their straightforward
approach to describing a complex network of design consider-
ations, Alexander, Ishikawa, and
Silverstein all anticipated and
inspired contemporary methods
for design thinking. By seeking to provide “a natural way
of expressing thoughts about
the physical environment,” the
authors offered a vital means
to articulate the richness not
only of a design solution, but its
problem and its context [ 6]. At
the same time, the earlier publication of Pattern Manual serves
as a reminder for elements of
patterns that often receive less
focus. At the heart of every pattern is a design problem. When
well defined, the design problem
represents the designer’s collective expertise of issues, information, and problem context,
making for better patterns and
design solutions. In examining
how the pattern language developed, we see how important
the latter parts of that sentence
were to Alexander and his colleagues—and to the continued
evolution of design thinking in
general. With straightforward
language, the problem and pattern language continue to bring
a systematic approach to design
to the wider audience who practiced it, improved upon its elements, and continue to develop
the concept today.
[ 9] Alexander, C.
Theory, Organization,
Activities. [Pamphlet],
Berkeley, Center
for Environmental
Structure, 1968.
ABOUT THE
AUTHOR Molly Wright
Steenson is a design
researcher and architectur-
al historian who studies
interactivity and respon-
siveness in architecture and urbanism. She
is a Ph.D. candidate in architecture at
Princeton University and contributing editor
for interactions. Steenson also conducts
research and develops design strategy for
mobile, Web, and urban projects and blogs at
Active Social Plastic ( activesocialplastic.com).
March + April 2009
DOI: 10.1145/1487632.1487637
© 2009 ACM 1072-5220/09/0300 $5.00