Colours for the blind

I took my first picture of the abstract patterns of tiles on Thessaloniki's pavements 10 days ago when they were shiny in the rain and I have been enjoying them ever since. Walking to the airport bus this morning it finally dawned on me that these multicoloured pavements are to help partially sighted and blind people to get about. The yellow, which would guide a stick pretty well, is down the middle of pavements. If there is an obstacle, such as a bus stop, there is a bobbled yellow tile to show a change of direction, then the yellow path leads the blind person round the obstacle. The white fine-striped tiles are one row bordering an obstacle, and the red tiles border trees. Interesting and useful things happen at road crossings, but I'd have missed my plane home If I'd stopped to decode it all.

Brilliant.