Wall
    pictures = { -- SpriteVariations
        single
        straight_vertical
        straight_vertical_under_ending
        straight_horizontal
        corner_right_up
        corner_right_down
        corner_left_down
        corner_left_up
        t_up
        t_down
        t_left
        t_right
        cross
        ending_up
        ending_right
        ending_down
        ending_left
    }
