"..In 1958 Gordon Spitzmesser patented the petrol-powered pogo stick "for the amusement of children and adults alike". And in particular, one assumes, the amusement of those watching.
Naturally it could be adjusted for "perfect performance for any specified weight"; what happened when it was adjusted for imperfect performance was presumably a brief and invigorating lesson in basic ballistics.
Needless to say, Mr Spitzmesser did not retire a billionaire.."