: (=permutation-static-array) ( -- array ) { 0 1 2 3 4 5 6 7 8 9 } ; inline

: =permutation ( x y -- ? )
    (=permutation-static-array)
    {
        [ [ drop 0 ] change-each ]
        [ '[ 10 /mod _ [ 1+ ] change-nth dup 0 > ] loop drop ]
        [ '[ 10 /mod _ [ 1- ] change-nth dup 0 > ] loop drop ] 
        [ ]
    } cleave
    [ 0 = ] all? ;