@Heliograph okay but prisms are akshually cruel and unusual punishment for light. Prisms break down an otherwise holistically healthy beam of light, break it down so hard it's fractured -- fractured! -- into all the delicate components of itself, forever changed by the ordeal.
I say ABOLISH PRISMS!!
edit: this is ignoring the horrific effects of dihidrogen-oxide -- which is EVERYWHERE -- on innocent photons