public void setCharacters(final String... CHARACTERS) {
        getCharacterList().clear();
        Arrays.stream(CHARACTERS)
              .filter(Objects::nonNull)
              .filter(character -> !character.isEmpty())
              .forEach(character -> getCharacterList().add(character) /*characterList.add(character.substring(0, 1)) */);
    }
Defines an optional node that can be used in combination with the
CustomTileSkin.
@param GRAPHIC
src/main/java/eu/hansolo/tilesfx/Tile.java