[ 0 swap
    [ dup while
      dup 1 &
      rot + swap
      1 >>
      again ]
    drop ]                    is popcount       ( n --> n )

  [ 1 & ]                     is odd            ( n --> b )

  [ odd not ]                 is even           ( n --> b )


  [ ]'[ temp put 0
    [ over while
        [ dup popcount
          temp share do
          if [ dup echo sp
               dip [ 1 - ] ]
           1+ ]
        again ]
    2drop temp release ]      is echopopwith    ( n -->   )

  say "Population counts of the first thirty powers of 3." cr
  30 times
    [ 3 i^ ** popcount echo sp ] cr
  cr
  say "The first thirty evil numbers." cr
  30 echopopwith even cr
  cr
  say "The first thirty odious numbers." cr
  30 echopopwith odd cr