▁In ▁Inter l isp , ▁Te itel man ▁invent ed ▁D W IM ▁(" Do ▁What ▁I ▁Mean "), ▁a ▁function ▁that ▁attempted ▁to ▁correct ▁many ▁common ▁typing ▁errors . ▁It ▁was ▁a ▁package ▁of ▁L isp ▁rout ines ▁which ▁would ▁" correct ▁errors ▁automatically ▁or ▁with ▁minor ▁user ▁inter vention " — th us ▁making ▁the ▁code ▁do ▁what ▁the ▁user ▁meant , ▁not ▁what ▁they ▁wrote . ▁The ▁program ▁was ▁developed ▁based ▁upon ▁Te itel man ' s ▁own ▁writing ▁style ▁and ▁id ios ync ras ies ▁in ▁ 1 9 7 2 , ▁and ▁then ▁used ▁by ▁other ▁individuals ▁in ▁his ▁office , ▁followed ▁by ▁users ▁across ▁the ▁industry . ▁In ▁ 1 9 7 7 , ▁he ▁and ▁Bob ▁Spr ou ll ▁implemented ▁the ▁first ▁client – server ▁window ▁system , ▁D - L isp . ▁D - L isp ▁used ▁the ▁Al to ▁as ▁a ▁display ▁device ▁on ▁which ▁ran ▁the ▁window ▁manager ▁and ▁event ▁handler , ▁communic ating ▁with ▁Inter l isp ▁running ▁on ▁a ▁MAX C ▁( a ▁P DP - 1 0 ▁clone ). ▁ ▁This ▁system ▁pione ered ▁such ▁concepts ▁as ▁over la pping ▁windows ▁where ▁the ▁window ▁containing ▁the ▁focus ▁did ▁not ▁have ▁to ▁be ▁on ▁top ▁to ▁receive ▁events , ▁on - line ▁context ual ▁help , ▁and ▁the ▁ability ▁to ▁cut , ▁copy , ▁and ▁paste ▁from ▁previous ▁commands ▁given ▁to ▁the ▁shell . ▁ ▁Other ▁research ▁He ▁joined ▁the ▁C ed ar ▁project ▁in ▁ 1 9 8 0 ▁and