Ever changing art

This is Geelong's answer to that graffiti artist paradise, Hosier Lane in Melbourne. They paint over existing designs quite regularly. I rather like the colours they have used for this curious mural. It makes me think about the designated colour pallet for 2014 that I downloaded and refer to regularly in my design of handouts in church.
Somehow, we know that a particular hue is wrong or 'out of date', (consider avocado bathroom suites), but how subtly these 'new' colours are brought into our awareness.