Gas Man

They go around the streets of Egypts cities, towns and villages selling gas canisters and removing the empty ones for refilling. The usual mode of transport is on a trailer being pulled by a small donkey. They announce their presence by banging loudly on one of the canisters with a big wrench, one of the empty ones we hope. This prompts the vendors in neighbouring streets to do the same, as they try to outwit each other to get the most customers. This results in a cacophony that waves around the town. They all bang the same rhythm which sounds uncannily like the old theme tune to Test Match Special!