31st Annual Collectors Convention Designer Autograph Sheet for Steve Vandervate, Hot Wheels Graphics Designer. This print depicts the Hot Wheels Gassa Nova. Hot Wheels and Mattel designers and guests are invited to spend time with the collectors and provide signed prints of their individual vehicle designs or graphics designs. These autograph sessions are a big hit amongst collectors with many standing in line for up to two hours at a time to have the opportunity to talk to the designers and have them sign various collector items .