It was so simple. Take a small flake of graphite and put it on piece of regular old Scotch tape. Pinch it in between the tape, peeling off layer after layer until it leaves only the vaguest, most transparent of marks. Transfer those dustings onto a chip; stick the chip under the microscope.

Congratulations, you've just made graphene—the strongest material humans are aware of. It's only one layer of atoms thick, which means to slice it any thinner would require dividing atoms into their elementary particles.

For years, scientists didn't even believe that creating graphene was possible—even Andre Geim, one of the scientists responsible for the scotch tape discovery. As he told CNN

We live in a 3-dimensional world. My physics intuition, developed over the last thirty years, told me that this material shouldn't exist. And if you had asked 99.9% of scientists around the world they would have said the idea of a 2D material was rubbish and that graphene shouldn't exist.

But it is possible to make it. The problem now is that it's not exactly practical.

There's so much graphene can do. It can make computer chips much, much faster. It can make solar cells more efficient. It can remove salt from water.

Any of these (and there are so many other) applications, though, require more than a tiny flake of graphene, and scaling up production requires something other than a really big piece of scotch tape. As Nature reported last year, when manufacturers rely on the tape method, "just one micrometre-sized flake made in this way can cost more than $1,000 — making [graphene], gram for gram, one of the most expensive materials on Earth."