@type t() :: %Boxart.Charset.Box{
  bottom_left: String.t(),
  bottom_right: String.t(),
  horizontal: String.t(),
  round_bottom_left: String.t(),
  round_bottom_right: String.t(),
  round_top_left: String.t(),
  round_top_right: String.t(),
  top_left: String.t(),
  top_right: String.t(),
  vertical: String.t()
}