Probably so. Higher-end stereopticons had this, as did most opera glasses. Numbering probably wouldn't be necessary as adjustment is pretty easy - like with modern binoculars, but like modern binoculars some manufacturers might want to mark index points.

Ghostbusters was a tv show in the 70s, a movie and cartoon in the 80s.

If you look closely you'll see that's not a handle on the glasses, it's a stand.

At which point making a metal gun on a desktop mill (products that are available now) would also be just as easy. It's not having access to the machines that's the tricky part, it's designing the code sets for them to make the part properly. Any advancement that improves that for CNC additive manufacturing will be…

So if a sheriff's department flies a light plane or helicopter and shoots pictures/video from the pod underneath it, that's all fine and good, but if the pilot is on the ground flying a drone by remote control to do exactly the same thing, we need new laws?

"Believe it or not, 3D printing requires some skill. And when you don't have it, things go delightfully askew."

The useless whistle cost pennies in materials. It's the operator's time and the cost of the machine that are high.

How deep will you dive? The GoPro Hero 3 is only rated to 10'.

Moreover, GoPros are bulky, boxy snapshot cameras.

For anyone to consider flying with water-rocket boots to be boring or "totally mundane" and in need of a GoPro to be livened up, they must be leading an exceptionally adrenaline filled life.

Right now, that cost is infinite, because there is no technology for 3D printing bullets.

" transmits a wireless signal, presumably over a Bluetooth connection"

What the report didn't say was that all 12 weapon system designs that were stolen were variations of the Liberator 3D printed single-shot pistol.

Plastic and lead is no match for the chocolate bullets Joe Beiden says would make the world a happier place:

"the first full-scale airplane, the Sperry M-1 Messenger"

Shotguns have smoothbore barrels - no rifling.

"Making the exact same slug out of lead."

"Mortars of just about any size actually are very easy to build."

Yep.

Yes, there are a number of reasons someone can't buy a firearm that requires a background check which aren't criminal (they aren't convictions though, since there are not crimes involved of which one could be convicted), and they're all asked about on the transfer application form.