Oracle - streng kombinatorisk permutation

Edit:Fik den generiske. Virkelig simpelt i sidste ende (men tog mig et stykke tid at nå dertil)

WITH words AS
(   SELECT  REGEXP_SUBSTR( '&txt', '\S+', 1, LEVEL )    AS word
        ,   LEVEL                                       AS num
    FROM    DUAL
    CONNECT BY LEVEL <= LENGTH( REGEXP_REPLACE( '&txt', '\S+\s*', 'X' ) )
)
SELECT  SYS_CONNECT_BY_PATH( W.word, ' ' )
FROM    words   W
CONNECT BY NOCYCLE PRIOR W.num != W.num

Edit2:Fjernede overflødige maxnum-ting. Tilbage fra tidligere forsøg