Hacker News Reader

Comment by noman-land | Hacker News Reader

I want an automatic scrambling machine, not an automatic solving machine. Two cubes. While you're solving one, the other one is being scrambled. Cubers spend way more time scrambling than solving. Scrambling is the annoying part that needs automating.

View on HN

This is in my mind the hardest part as well.

I can solve the cube with the regular “easy” 3-layer approach, but I’d like to solve it faster.

The issue is that the techniques for fast solving require to learn many different patterns to get to the right solution fast.

I don’t know really how ppl that solve it fast accomplish getting to that level, but to me it would be amazing if i could just set the cube in know scrambled states that let me practice and memorize specific algorithms repeatedly until I learn them.

The problem is that I don’t know enough yet to distinguish which are those initial states, let alone setting the cube in that state, so something that could set it up for me to practice would be amazing

> I don’t know really how ppl that solve it fast accomplish getting to that level

Just like everything else in life, they do it really slow and with lots and lots and lots of errors at first, but (and this is where the magic happens) keep doing it, training hours a day or their entire week ends, for years.

I’m completely not in this space but your comment had me wondering: are there digital cube faces? That is, a real physical cube but with faces that can instantly be set to a given color?

This is a great question! Doesn’t seem like it’d be hard to make if it doesn’t already exist

They exist, but one of the problems is they're not particularly good cubes. While it might help you learn the basics, not being able to handle it like a speedcube means they're probably not going to help you get faster.

https://m.youtube.com/watch?v=l-TWH5W-1fw

https://exmarscube.com/product/ex-mars-ai-robot-cube/

That being said, while looking up those links, I found out that, since I got out of the hobby, smart cubes have become a thing, and are made by real speedcube manufacturers.

https://www.gancube.com/products/gan-356-i-carry-smart-magic...

This is an easier problem to solve. I'm not sure if you have to solve it first or if it can identify pieces on power up, but after that it's just tracking rotations, which can be done from the (fixed position) centres alone. But if an actual speedcube manufacturer can already fit those electronics in without comprising performance, I can't imagine it's that much harder to fit some addressable LEDs on some slip-ring-esque connections. Must just not be much of a market.

At least until a certain level, scrambling (according to a given "algorithm") is a good way to practice moves. It shouldn't take much longer than a solution either, you are not solving the cube in under 30 moves. And if you don't care about the scramble it's even faster. So I don't think the "way more time" is entirely accurate. It may feel like it though.

Can’t you just run the solving machine in reverse?

You can but it doesn't need to be smart at all. It doesn't need cameras. It's a much simpler machine.

Funny enough, that (e: the shuffle function mentioned in original thread post, just realized my awkward comment placement) sounds like a very reasonable stretch goal/feature add-on, although I'm not sure this particular machine could shuffle quickly enough for speedcuber types.

It needs to be somewhat smart, if you want to track your scrambles and times. But yes, it doesn't need cameras if it trusts you.

Yeah, it's just a software change to the existing machine. If you generate a target scrambled state it's literally the solver algorithm in reverse too.

It would be neat if it offered to scramble when you insert an already solved cube (demoed in the video), and maybe have options for the amount of randomness.

Is there an unbiased scrambling (or random generation) algorithm, or is it enough to just generate N random moves?

To answer my own question, competitive cubing uses unbiased randomization algorithms.[0] To minimize scrambling time, it could fairly generate a random configuration and then optimally scramble the cube in ~18 moves.[1]

TL;DR fair scrambling is exactly as fast (same throughout) as solving random cubes! Neat.

[0] https://www.cubelelo.com/blogs/cubing/how-to-scramble-a-rubi...

[1] https://en.wikipedia.org/wiki/Optimal_solutions_for_the_Rubi...

Reply on news.ycombinator.com