That's the idea behind one Reddit post that proposed building a citywide scavenger hunt in San Francisco with hundreds of 3D printed toys. The man behind the post is Ben Baltes, a 25-year-old software developer who is a co-founder of a 3D printing toy start-up in Oakland. In a phone call Monday with Mashable, Baltes said he's been thinking about the project for about two years and is framing it as "more of an experiment than a game.