It's probably not a good idea to secure your valuables in a safe that could be easily circumvented by a toddler. Even if it does have a working combination lock. So we'll just file this papercraft safe under educational novelty.
And if you've always been curious how a combination lock works, or if you're an infamous jewel thief who wants to pass on the trade to their kids, you can download the plans and instructions here. [Robives via BoingBoing]