Popular form of recycling unwanted material - shopping trolleys, mattresses, bricks, old prams, other people's schoolbags, etc. Derived from the ancient Scottish superstition of the "cannyfish", wherein once a thing is thrown into the magical canal, it decomposes and turns into beautiful goldfish. These goldfish are captured and grant to their captor a single magical wish. Most people, alas, thinking themselves clever, ask for unlimited wishes, which cheek usually gets them a smack in the mouth and a consolation prize of a manky stripped couch to throw into the canal again.