markStartFinish :: Int -> Int -> Grid -> Grid
markStartFinish start finish (Grid dims sqs) =
  let
   sqs' = Unboxed.imap (markSF start finish) sqs
  in
    (Grid dims sqs')
markStartFinish :: Int -> Int -> Grid -> Grid
markStartFinish start finish (Grid dims sqs) =
  let
   sqs' = Unboxed.imap (markSF start finish) sqs
  in
    (Grid dims sqs')
markStartFinish start finish (Grid dims sqs) =
  let
   sqs' = Unboxed.imap (markSF start finish) sqs
  in
    (Grid dims sqs')