: has-all? ( tested-seq requirements-seq -- ? )
    [ swap member? ] with map [ ] all? ;

    
: have-all ( seq^2 requirements-seq -- matches ) 
    '[ _ has-all? ] filter ;
    
: most-is-n ( seq -- n/2+1 ) 
    length 2 /i 1+ ;    
    
: most-items ( seq^2 -- most-seq )
    [ concat ] [ most-is-n 1- ] bi
    [ duplicates ] times prune ; 
! I'm not sure about the use of duplicates here, though it seems like it's correct

: mostly-intersect ( seq^2 -- seq )
    dup most-items have-all ;