I visited the supermarket this morning and as I approached the door with its compliment of shopping trolleys I recalled the last time I visited. After unloading my trolley into the car I pushed it across the car park towards the trolley rack with the intention of retrieving my coin which is held captive as an incentive to return the trolley and lock it up again to stop it being abandoned at some far corner of the planet. That day I saw two blokes looking quite puzzled as I approached the rack. Both were tapping their sides, searching their pockets for a coin in order to release one of the trollies from captivity. Seeing their dilemma I offered them my trolley which they accepted with thanks.
Image source:http://www.flickr.com/photos/alphageek/121953651