Homepage - now with Rubik's Cube solution

Pages: 12
Holy crap, that tutorial is beautiful. Although when I read the title of this thread I thought it would be a program of some sort to solve Rubik's Cubes :P
@ascii
Sort of true. While there are various steps that can aid you for the cross and F2L a significant portion of it is understanding how the pieces move around, something that's not really easy to teach.
Well first off I would explain that you should first solve the first layer edges and then the corners. For solving the edges I would make sure the people reading the tutorial knew too:
1. Keep the Cross you make on top (the U face).
2. Too solve the edges, first find a white edge, put it on the down face, rotate the down face until the non-white color of the white edge matches the center piece of whatever face it is on and then just rotate the face upwards twice.
3. The algorithm for inverting the colors of an edge piece (R' U F U').

I might not have explained this very well, but I think all of my points are explained more clearly and with diagrams on page 3 of this PDF: http://www.rubiks.com/solving-center/pdf/Rubiks_cube_3x3_solution-en.pdf

As for solving white corners, I think it would be useful too explain what the correct position of an edge is (as in, it's final position), how too rotate a corner so that it is directly under its correct position, and the algorithm too bring it up too it's final position (R' D' R D). Again, all of these points are explained on page 4 of the PDF I linked above. If you want too add some other useful algorithms for this step, you could put in some of the ones at the bottom of this page: http://cubewhiz.com/beginner1corners.php.

These are just my two cents, anyhow, and I still think it's an excellent tutorial.
Holy crap! The official tut is fabulous -- even if it uses weird notation and a couple of other oddities.

Your explanation is fine.
Perhaps I'll just add tips like "do the cross first" and links to other stuff?

I tend to think that most gradeschoolers can at least get one face solved... but maybe I'm making it too hard?

I'll mess with it when I get some time.
Perhaps I'll just add tips like "do the cross first" and links to other stuff?

Sure, that sounds good.


I tend to think that most gradeschoolers can at least get one face solved... but maybe I'm making it too hard?

I'm not really sure, I never tried too do it without any preexisting knowledge of some basic algorithms.

There's no algorithm to solving the cross. It's actually the only point you must do intuitively, so the best tip you can really give there is just to do it a lot.

There's no algorithm to solving the cross. It's actually the only point you must do intuitively, so the best tip you can really give there is just to do it a lot.


I disagree. Using this definition of an algorithm from google: "A process or set of rules to be followed in calculations or other problem-solving operations," there definitely is an algorithm too solve the cross, as I will provide below (in my example we will be solving a white cross):
1
2
3
4
5
6
7
8
9
10
11
12
13
14
1.  Find a white edge piece.

2.  Keeping the white face on top (as in, keeping it as the U face), rotate either of the faces the edge piece is on until one of the faces the edge piece is on is the D face.
      a.  This may dislodge some of the white edge pieces that have been
           solved.  If so, rotate the D face once in any direction and then undo
           whatever rotations were made too put the white edge piece on the 
           D face.
3.  Rotate the D face until the non-white color on the white edge piece matches the center piece of whatever face it is beneath.

4.  Orient the cube so that the face with the white edge piece on it is the R face.  Then, rotate the R face twice.
      a.  If after performing this step the white edge piece is not on the U
           face but the R face, perform the following algorithm:  R' U F' U'

5.  Repeat steps 1-4 with each of the three remaining edge pieces.  


If you follow these 5 clear steps you will solve a cross: an algorithm does exist.
Last edited on
These steps being clear is dubious at best. For example: "Rotate whatever face the white edge piece is on until it is on the D face." doesn't make any sense. The only piece that can exist on one face is the center piece. The white edge piece is going to exist on two faces. You can't "rotate the face the white edge piece is on" without a definition of which face to rotate. If it means rotate the face the white face of the edge piece is on, rotating that face will not position the white face on the D face unless it's already on the D face, otherwise it'll either position its counterpart on the D face, or always keep it on the U face.

To explain an algorithm to solve the cross means you must explain how the pieces move when you turn a face. So I guess, yes, technically an algorithm does exist, but what you need to do to properly describe the algorithm essentially means you're describing the movements of the pieces. And this description will be long and wordy and honestly most people will do better figuring out the intricacies by doing rather than by reading.

Edit: Basically these steps are so unclear that I have to use my pre-existing knowledge of how to solve a rubix cube to interpret what the steps want you to do.
Last edited on
Okay, so the steps were poorly explained, sorry (it's hard too explain without diagrams). My point still stands, anyhow: there is an algorithm too solve the cross. I was trying too show that what you said before was incorrect, so whether or not I didn't explain my steps very clearly, I created a functioning algorithm.


The only piece that can exist on one face is the center piece. The white edge piece is going to exist on two faces. You can't "rotate the face the white edge piece is on" without a definition of which face to rotate. If it means rotate the face the white face of the edge piece is on, rotating that face will not position the white face on the D face unless it's already on the D face, otherwise it'll either position its counterpart on the D face, or always keep it on the U face

I have now reworded that part too make it clear that either face can be rotated.
Last edited on
I should perhaps clarify what I meant by there not being an algorithm for solving the cross. What you need to solve the cross is ever-changing and dependant on the current state of the pieces, meaning you must use a series of algorithms for moving the pieces in the state they're currently in, but you can't be sure about the order in which you must use those algorithms.

So regarding my initial statement about there not being an algorithm for the cross, there's really not, I could have been more clear about it though. There are algorithms to solving the individual pieces that lead you to a cross, but not one specifically for the cross.

Edit: Essentially they're algorithms for moving pieces, and you can use them to make a cross, but they're not specific for making a cross, just for moving pieces.
Last edited on
Topic archived. No new replies allowed.
Pages: 12