6 ▁he ▁joined ▁O ve ▁A rup ▁& ▁Part ners . ▁In ▁ 1 9 5 7 ▁he ▁took ▁leave ▁to ▁purs ue ▁post ▁gradu ate ▁studies ▁at ▁Imperial ▁College ▁rejo ining ▁A ru ps ▁in ▁ 1 9 5 8 . ▁After ▁three ▁years ▁working ▁on ▁J ør n ▁Ut zon ▁shell s ▁for ▁the ▁roof ▁of ▁the ▁Sydney ▁Opera ▁House ▁in ▁London , ▁where ▁he ▁is ▁cred ited ▁with ▁having ▁done ▁the ▁geometry ▁for ▁the ▁problem atic ▁design , ▁he ▁moved ▁to ▁Sydney ▁to ▁be ▁assistant ▁engineer ▁to ▁Ian ▁Mac K en zie . ▁After ▁one ▁month ▁Mac K en zie ▁fell ▁ill ▁and ▁was ▁hospital ised , ▁leaving ▁R ice ▁in ▁total ▁charge ▁at ▁the ▁age ▁of ▁ 2 8 . ▁On ▁site ▁his ▁geomet rical ▁knowledge ▁enabled ▁him ▁to ▁write ▁a ▁computer ▁program ▁to ▁locate ▁the ▁segments ▁of ▁the ▁shell s ▁correctly . ▁In ▁total ▁he ▁spent ▁seven ▁years ▁working ▁on ▁the ▁project . ▁After wards , ▁he ▁spent ▁ 1 8 ▁months ▁in ▁the ▁United ▁States , ▁in ▁New ▁York ▁City ▁and ▁as ▁visit ing ▁scholar ▁at ▁Corn ell ▁University . ▁ ▁Pom pid ou ▁Centre ▁( Be a ub ourg ) ▁ ▁In ▁ 1 9 7 1 ▁he ▁was ▁part ▁of ▁the ▁winning ▁team ▁compet ing ▁in ▁the ▁French ▁government ' s ▁competition ▁for ▁the ▁centre ▁of ▁Paris ▁at ▁Be a ub ourg , ▁partner ing ▁Richard ▁Rog ers ▁and ▁Ren zo ▁P iano . ▁Edmund ▁H app old ▁was ▁the ▁senior ▁A rup ▁engineer ▁for