Geograph - photograph every grid square

Graffiti or art?
These mosaic pieces by the French street artist 'Invader' have brightened up the darker places of many cities around the world for several years Link The 'Alien Invasion' of Newcastle took place in 2006 Link The captions to the site photographs clearly indicate that the Newcastle Police did not hold strongly with the art viewpoint, but many pieces are still in place some four years later. Most people now probably fail to see them at all, or think, like I did when first seen, that they were some kind of survey marker or 2D code. The penny dropped for me after seeing a post on the Newcastle Metro Area forum of SkyscraperCity Link
However, there is local evidence for close encounters NZ2464 : The aliens have landed
'Watch this space for invaders' Link
Invader in Wikipedia Link