MADRID.- The architecture of Raili (born 1926) and Reima (19231993) Pietilä, which became world famous during the 1960s, is experiencing a second coming in this exhibition, which uses original drawings to present the work of the husband and wife team in the form of some previously unseen designs and others that have attained iconic status in the history of architecture. A host of sketches shows, in a fascinating way, how in their search for design solutions every possible alternative is of equal value to start with, until eventually, the buildings acquire their final forms forms which stretch the boundaries of modern architecture. The various models give the visitor an opportunity to observe, for example, how the architecture of the Presidents Official Residence, Mäntyniemi (198393), evolved from the competition-winning proposal to the finished building. At the same time as the Pietiläs began searching for a way forward for modern architecture, Reima Pie