Nintendo X said:Project Reality ----> Ultra 64 -----> Nintendo 64
The first two were codenames for N64, however, U64 was a arcade hardware, and codename for the system...Its sad, because it was more recognized more than N64 ever was, because some big names were powered by it.
Bzzztt.. wrong! Ultra 64 was the official name of the N64, in America. Nintendo couldn't get that copyright for the whole world though, so in the end they changed the name to Nintendo 64 so the system would have a universal name.