Sometimes it is difficult to see how a combination of technological developments can have an exponential impact on society. The video below shows a very good example of this.
A guy was able to fire a few bullets with a 3d-printed gun before breaking apart. Think about the impact of this. Suddenly gun-control is no longer something that can be enforced by rules and regulations, metal detectors just became useless in detecting guns.
The design may still be flaky, but it is already out there. All you need is access to a 3d-printer and a very small file containing the design.