def rgb_offset(r, g, b)
      16 + (36 * scale_color(r)) + (6 * scale_color(g)) + scale_color(b)
    end
def rgb_offset(r, g, b)
      16 + (36 * scale_color(r)) + (6 * scale_color(g)) + scale_color(b)
    end
0x10-0xE7:  6 × 6 × 6 = 216 colors