The last time I saw this sort of colour referencing was way back in primary school ( a couple of decades ago) when teachers used to use pink and blue cards to write out the personal details of girls and boys respectively.Around that time, there was no provision for those who fell in between and nobody really gave a shit about gender sensitivity or sexual orientation `Sorry lad, you're only allowed to choose one colour.' `But sir, I'm a little bit blue and a little bit pink.' Suvarnabhumi International is probably the only airport in the world that enhances its toilet pictograms with the same colour codes. Is this a colourful attempt to avoid confusion? Nah!! This isn't Scotland. Either way, I suppose each airport has its own peculiar system for the separation and classification of shit.