sentences:  In 1965–66 he returned to Quito to teach at the National Conservatory, but then moved back to Germany to attend the Internationale Ferienkurse für Neue Musik in Darmstadt, and the Fourth Cologne Courses for New Music in 1966–67, where he studied with Karlheinz Stockhausen (; ).He is regarded as one of the central figures of the Cologne School, active since the mid-1970s .Maiguashca worked closely with Stockhausen in the Electronic Music Studio of the Westdeutscher Rundfunk in Cologne from 1968 to 1972, and joined Stockhausen's ensemble for performances at the German Pavilion at Expo '70 in Osaka.