77Many buildings require courtyards for illumination.
Windows and doors that look out onto courtyards, which
may even be only diminutive air wells with glazed roofs that
hardly qualify as exterior spaces, give the impression of open-
ing towards the outside. Here, the outside world does not
seem shut out, as it does when illumination is purely via sky-
light. The rear courtyards of apartment buildings, however,
are often reduced to the status of light shafts, which moreover
may interfere with coexistence by transmitting noise between
units.
Building and courtyard enter into a time-tested connec-
tion in the courtyard house, with the patio or atrium house
found among the most incisive architectural > types. In an evi-
dent correspondence between form and lifestyle, the spaces of
courtyard and house form a cohesive structure. Examples are
the Roman atrium house and the traditional courtyard house
(hutong) in Beijing. In the courtyard complexes of multi-
storey buildings, for example the ‘Wiener Wohnhöfe’ (i.e. the
spacious courtyards of Viennese apartment buildings), the
courtyard is a semi-public space and is intended for the com-
munity.
The compluvium, the rectangular opening in roofs of
Roman residences, through which rainwater flows in from
all sides to enter a basin (impluvium), is interpretable as an
animated emblem of a centripetal or introverted > figure of
movement: as a space of > access, the courtyard is simulta-
neously a centre where occupants, entering from the ring of
surrounding rooms, engage in activities that require light, air
and room for movement, and a setting for receiving guests.
Conversely, this > spatial structure can also be conceived as
centrifugal, since movement flows from the community space
of the courtyard with diminishing degrees of > accessibility
into individual zones. In courtyard houses where a passage-
way runs around the perimeter, separating open space and
surrounding rooms, especially as an arcade (peristyle court-
yard), concentric > circulation is added as a characteristic