[travisgriggs]

Not a (speed) cuber, just a guy that uses the memorized algorithms to do it slowly when my mind wants something to distract it.

What makes me curious is the variance in how the cubes are initially scrambled. Surely some cubes are easier to solve than others? So I have to believe there’s an intersection between skill AND luck of the draw?

As a tournament watcher, these things go so fast, there’s no real build for the spectator either.

Why don’t they do “here’s a paper bag with 10 scrambled cubes—solve em all!” This would reduce the outset variance and allow for some excitement to build in the room. At the rate these guys go, it would still be over in 2 minutes.

Those looking for a slower pace could still watch a chess tournament if need be.

[mrandish]

I'm no expert but I took my kid to a speed-cubing event and we watched. The referees secretly set up the hidden cubes to be used for competition to specific randomized configurations which are determined automatically by a software program for each cube. I assume this program ensures that no competition cubes are scrambled such that they are excessively easy to solve.

[muti]

Interestingly, the rules only stipulate a minimum of two moves to solve. The implementation details of the official scrambling program may be stricter though

https://www.worldcubeassociation.org/regulations/#4b3

[nsilvestri]

The scrambling program tnoodle is open source and you can check out the implementation. [0]

I haven't verified myself, but I do think there is checking involved for some of the events (at least 3x3, 2x2, skewb, square-1, and pyraminx) to make sure the puzzles hit the minimum move limit. Other events like 5x5+ just use a sufficient number of random moves, because it would take too long to find and verify optimal solutions.

I can say in practice that the 2 move limit for 3x3 isn't a problem. I work on some personal projects related to cubing and was exploring the database [1] which has many historical scrambles. The shortest scramble ever generated was 12 moves long [2], and, from what I could tell from an extended inspection, is only "kind of" lucky. It's possible that some other simpler solves exist in the database but I haven't set my computer to crunch out the optimal solutions just yet.

I'm not particularly worried about really-short scrambles being randomly generated; my back of the envelope calculations suggest 3x3 scrambles of 8 moves or less as being one in 3.6 billion, while ~310,000 have been generated since 2014 and I estimate a seventh of them are never used (extra scrambles generated for a round if something goes wrong like the timer malfunctioning, the judge not following protocol, etc.).

[0] https://github.com/thewca/tnoodle

[1] https://www.worldcubeassociation.org/results/misc/export.htm...

[2] https://www.worldcubeassociation.org/competitions/SofiaAutum...