This is the text from a leaflet on the subject.
A biotope for time.
Modern air travel transforms our subjective sense of time. Todays airline passengers can cover distances within a few hours that would have entailed weeks of travel just a century ago. On extended flights, the jet aeroplane seems to recind the natural laws of time and duration. As they enter succesive time zones, passengers routinely readjust their wristwatches several hours backward and forward in time.
Mobility and speed are attributes of the spirit of our time, but our times do not deal gently with time. Saving time, killing time, wasting time phrases like these have become postulates of postmodernism whether as working hours, periods of rest or leisure time, only when time is linked to a concrete function do we grant it the right to exsist. Wilheli Holderied's and Karl Schlammingers AN ISLAND IN TIME represents an alternative vision, a place where time exsists and passes for its own sake alone. No longer the means to an end, time has become an end in itself; and this extraordinary artwork is an expressive means to that end. Time is not here; instead, in the rhythm of spring, summer, autumn and winter, time itself impressesits stamp upon the "Earthsign." An air traveller is ideally situated to appreciate the full dimension of this monumental sculpture's gravel walls and curving furrows. Immediatly after takeoff or before landing, passengers have a brief oppotunity to view the Earthsign. As a greeting from another time, a time untouched by flight plans or appointment calenders, this artwork invites its beholders to muse and to reflect. Anyone who allows himself or herself to embark on this journey in thought is granted a unique oppotunity to create his or her own Island in Time.