It's like the good old Amiga 500 palette.
[[File:{| style="border-style: none" border="0" cellpadding="0"|-|| http://upload.wikimedia.org/wikipedia/en/d/d7/RGB_12bits_palette_color_test_chartRGB 12bits palette color test chart.png]]|| http[[File://upload.wikimedia.org/wikipedia/en/4/47/RGB_12bits_paletteRGB 12bits palette.png|}]]
Systems with a 12-bit RGB palette use 4 bits (16 values) for each of the red, green, and blue color components. This results in a 16<sup>3</sup> = 4096 colours palette.