, ▁who ▁file d ▁a ▁pat ent ▁on ▁a ▁rot or ▁machine ▁in ▁ 1 9 1 9 . ▁At ▁about ▁the ▁same ▁time ▁in ▁Sweden , ▁Ar vid ▁Ger hard ▁D amm ▁invent ed ▁and ▁pat ented ▁another ▁rot or ▁design . ▁However , ▁the ▁rot or ▁machine ▁was ▁ultimately ▁made ▁famous ▁by ▁Arthur ▁Sch erb ius , ▁who ▁file d ▁a ▁rot or ▁machine ▁pat ent ▁in ▁ 1 9 1 8 . ▁Sch erb ius ▁later ▁went ▁on ▁to ▁design ▁and ▁market ▁the ▁En igma ▁machine . ▁ ▁The ▁En igma ▁machine ▁ ▁The ▁most ▁widely ▁known ▁rot or ▁ci pher ▁device ▁is ▁the ▁German ▁En igma ▁machine ▁used ▁during ▁World ▁War ▁II , ▁of ▁which ▁there ▁were ▁a ▁number ▁of ▁variants . ▁ ▁The ▁standard ▁En igma ▁model , ▁En igma ▁I , ▁used ▁three ▁rot ors . ▁At ▁the ▁end ▁of ▁the ▁stack ▁of ▁rot ors ▁was ▁an ▁additional , ▁non - rot ating ▁disk , ▁the ▁" reflect or ," ▁w ired ▁such ▁that ▁the ▁input ▁was ▁connected ▁elect r ically ▁back ▁out ▁to ▁another ▁contact ▁on ▁the ▁same ▁side ▁and ▁thus ▁was ▁" reflect ed " ▁back ▁through ▁the ▁three - rot or ▁stack ▁to ▁produce ▁the ▁ci pher text . ▁ ▁When ▁current ▁was ▁sent ▁into ▁most ▁other ▁rot or ▁ci pher ▁machines , ▁it ▁would ▁travel ▁through ▁the ▁rot ors ▁and ▁out ▁the ▁other ▁side ▁to ▁the ▁l amps . ▁In ▁the ▁En igma , ▁however , ▁it ▁was ▁" reflect ed " ▁back