Also, I've never understood why green is a primary color of light, but not when it it comes to mixing paint. Instead, it gets replaced by yellow. Why aren't the colors the same in both cases?
Where's Rainbow Brite when you need her?
Also, I think the spectrum actually IS linear rather than looped. If you go past violet, you go on to ultraviolet, rather than back to red. If you go backwards from red, you go to infared rather than back to violet.
As far as mixing the colors goes though, a looped spectrum seems to make more sense. Gah! Too confusing!