GiG is an "and-also" separator, I think. (That is, G ### G i G ### G is two phrases hooked together the way we would say "### and also ###".)
o is a hex-spiral raster image, as I said. n is an ordinary square raster read in matrix order. (The Cetis are *smart* puppies -- they knew that their raster style was probably not very common in the Universe, so they included a simpler one.)
I think pP ### Pp denotes "a picture of these symbols", and rP ### Pr denotes "a picture of what these symbols describe." qP ### Pq is probably another thing like this, but I'm not sure what.
Also, I think I found a typo in their message :-) (How's that for arrogance?)
(later)
hee hee. I know what they look like. And since this Web interface doesn't allow linefeeds, I can't show you folks.