We have to have 3 codes, 1 to 255, to create a rgb color, which we do with length, width (and most likely height) of any SL sim location (same codes of 1 to 255 for length and width, with 256 reverting back to 0). Here’s the color for 097 097 097, which is a variation of gray:
Here’s the colors 000 000 000 to 255 255 255 in increments of 032. This forms a stepped continuum of black through various grays to white:
The approx. rgb color of the 20 prim purple tower house situated directly in front of 097 097 097 Lanestris is 051 000 051. It seems to be very dark purple, with mainly even parts red and blue but little to no green.