Mark Southworth created Double Cross. Chris Smith manufactures the prop and gimmicks. Chris invented the Super Sharpie, Mark made a few changes to the design, and as far as I'm aware Chris Smith still manufactures the gimmick.
In essence, Mark was the architect and Chris Smith the contractor/builder. It was a team effort. Even on Chris's website, Chris calls it "Mark Southworth's Double Cross".
Chris is an excellent prop builder and he has built many props for other magicians.
Answered at 09:34am on April 16th, 2019 by joshburch (237 karma)