The crescendo of media reports about the advent of a DIY printable firearm has caused an understandable uproar. In the wake of so many high-profile, mass-casualty incidents involving firearms — and a lot of impotent rage by our elected officials — it seems counterintuitive that, as we circle the wagons around the idea of passing rational gun legislation at the federal level, we can also literally create a gun. When I was in high school, some classmates brought a crinkled copy of “The Anarchist’s Cookbook” that they printed off the Internet