This. The fact that the paper doesn't even mention the "Scientific Classification" path to Linnaeus is kind of ridiculous. I mean, sure, you can argue whether or not it's valid to include that or not, but the fact that it's systematic means it's at least important to point out.

As The boojum said, you can theoretically solve a cube in any configuration in 20 moves, but it might take a long time to find that optimal solution. Computers can quickly find a just-over-20-move not-quite-optimal solution, though.

Human-friendly algorithms generally take over 50 moves, with the absolute best solves still taking more than 40.

I stepped through this video frame by frame. They rotate the cube 5 times to inspect each face first (I guess they only have one camera), paused about 0.2 seconds (presumably to calculate a solution) and then they made 21 moves plus 4 rotations to solve it. (The rotations were necessary because it only has 4 arms and can't spin the top and bottom layers.)

So yeah, looks like they computed a nearly-optimal solution, and I imagine they can probably get a just-over-20-move solution every time.

2.5" Hard Drives have been stagnant though. While SSDs have been steadily improving, the biggest 2.5" HDD you could get a few years ago was 750 GB, and now it's still just 1 TB.

If it makes you feel any better, I work for a software company, and what you describe is exactly how I conduct interviews. I ask candidates to code, but I don't actually care that much if their program is bug-free. I care about how they go about doing it, and how they figure out solutions as I point out problems. I care more about the work they show than whether they happen to get this instance exactly right.

When I was growing up, my dad told me that none of the facts I learned all the way through high school mattered that much in the end, but what mattered is that going through it taught me HOW to learn.

I've also thought about how I have some friends who don't know any of my other friends. If either of us died, there would normally be no way for the other to find out about it through the grapevine. But now with Facebook, we would probably find out by seeing other people's wall posts. I think that's actually a valuable service.

I like what I saw in someone's sig on /. once:

"The trouble with Wikipedia is that it only works in practice, not theory." :P