▁ 3 ▁whe els ▁in ▁reverse ▁order , ▁III ▁II ▁and ▁I . ▁Un like ▁the ▁En igma , ▁the ▁whe els ▁here ▁do ▁not ▁control ▁their ▁own ▁movement : ▁this ▁is ▁done ▁through ▁ 3 ▁independent ▁pin - w he els ▁N 1 ▁N 2 ▁and ▁N 3 ▁with ▁periods ▁ 2 1 , 2 3 ▁and ▁ 2 5 . ▁The ▁figures ▁were ▁distributed ▁among ▁N 1 ▁N 2 ▁and ▁N 2 ▁in ▁possibly ▁two ▁different ▁configurations . ▁ ▁The ▁pin ▁whe els ▁have ▁a ▁uniform ▁motion , ▁i . e . ▁they ▁move ▁one ▁position ▁for ▁every ▁letter ▁key ed . ▁As ▁for ▁the ▁movement ▁of ▁the ▁key ▁whe els ▁and ▁other ▁details , ▁the ▁machine ▁passed ▁through ▁different ▁stages ▁of ▁development ▁in ▁the ▁course ▁of ▁time , ▁for ▁which ▁there ▁were ▁no ▁specific ▁names ▁and ▁which ▁will ▁be ▁denoted ▁here ▁by ▁a , b , c ▁and ▁d . ▁ ▁Each ▁of ▁three ▁whe els ▁moves ▁on ▁one ▁place ▁when ▁there ▁is ▁an ▁active ▁pin ▁at ▁the ▁sens ing ▁point ▁of ▁the ▁relevant ▁pin - w heel , ▁and ▁it ▁only ▁moves ▁then . ▁The ▁whe els ▁have ▁no ▁move able ▁rings ▁on ▁the ▁body ▁of ▁the ▁wheel , ▁with ▁the ▁result ▁that , ▁unlike ▁the ▁En igma , ▁the ▁initial ▁position ▁of ▁the ▁body ▁of ▁the ▁wheel ▁is ▁determine ▁absolutely , ▁at ▁the ▁same ▁time ▁as ▁the ▁clear ▁message ▁setting . ▁The ▁reflect or ▁wheel ▁is ▁pl ugg able ▁like ▁the ▁reflect or ▁wheel ▁D ▁on ▁the ▁En