The magician, Dr. Apollo, performed on the last platform nearest to the canvas fly leading to the blow-off.  He started by passing out to his audience a dozen shiny steel rings, each as wide as a plate; he invited them to convince themselves that each ring was solid and smooth.  Then he had them hold the rings so that they overlapped.  Dr. Apollo walked along the platform, reached out with his wand and tapped each overlap - the solid steel links formed a chain.