let h, w = Scanf.scanf " %d %d" @@ fun a b -> a, b
let a_ss = Array.init h @@ fun _ -> Scanf.scanf " %s" @@ fun s -> s
let s = String.make (w + 2) '#'
let _ = print_endline s; Array.iter (Printf.printf "#%s#\n") a_ss; print_endline s