This part is still under construction, apologies.
(state problem here)

Colours can change your mood, take movies for instance. A dark, grey scene indicates mourning and the absense of bright colours indicates a dreadful routine like a boring office job. 

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And removing 'green' entirely you get the openings scene of Wall-E, leaving a desolate and baren feeling. Almost dystopian. 

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To fully understand colours, a.k.a. coloured light, we need to understand light first. So, what is light exactly and how can light be used to laser in colour on stainless steel?