( ( fs
  =
    .   '$!arg:?arg
      &
        ' ( first r
          .   :?r
            &   whl
              ' ( !arg:%?first ?arg
                & !r ($arg)$!first:?r
                )
            & !r
          )
  )
& ( partial
  =
    .   !arg:(?f.?g)
      & /('(x./('(y.($x)$($y)))$!g))$!f
  )
& (f1=.2*!arg)
& (f2=.!arg^2)
& partial$(fs.f1):(=?fsf1)
& partial$(fs.f2):(=?fsf2)
& out$(fsf1$(0 1 2 3))
& out$(fsf2$(0 1 2 3))
& out$(fsf1$(2 4 6 8))
& out$(fsf2$(2 4 6 8))
);