Actually, I remember reading somewhere that cats have limited color perception. To a cat, red appears to be black. Don't know what green maps to, however... -al- -acorda(a)1bigred.com -----Original Message----- From: Eric Smith [mailto:eric@brouhaha.com] Sent: Tuesday, November 04, 2003 2:51 PM To: General Discussion: On-Topic and Off-Topic Posts Subject: Re: Cats ben franchuk wrote: Sellam Ismail wrote: Note that doing this for the purpose of exercising the cat may violate US patent 5443036. The patent makes no claims about doing it to entertain the human and/or the cat, however. The patent may be invalid anyhow, as it describes using a "beam of invisible light", which surely won't hold the cat's interest. A beam of red light works much better. I haven't tried a beam of green light, but green laser pointer prices have come down enough that it is tempting to try it the next time I'm in Colorado. (None of my close friends here in California have cats.) Eric