Sure Shot Paper Slinger
 
"In the open door he paused a moment for a good look at his greatest invention.  There it was, fastened to the rear wheel of his bike.  Man, oh man, it looked good!  Why he'd probably make a million dollars on it, besides helping every paperboy in the world.  It was a genuine, never-before-invented Sure Shot Paper Slinger."

The invention stood out on one side of the rear wheel.  There were a lot of complicated parts, but mainly it was made of a broom handle, an inner tube rubber, two screen-door springs, and a tube made of cardboard that was big enough to hold a rolled-up paper.  Two levers on the handlebars operated the invention.

'Oh, Alvin,' said the Pest.  'It's beautiful.'

'May not work,' he replied.  'May not work at all.  You never can tell about an invention until you test it.'"