# [CFOP] A tool to practice cross to transition to F2L



## net13 (Apr 8, 2015)

*[CFOP] A tool to practice cross and transition to F2L*

How to use:


Go here: http://net13.net/Cube/Cross/[1]
Scramble your cube as indicated.
Plan out your cross. It shouldn't be too hard, as it's only one move. 
Find an F2L pair.
Execute your cross while tracking your F2L pair.
So what did you just do? You planned out the entire cross in your head, then you solved it while tracking an F2L pair, allowing you to immediately get started on F2L. That pretty much makes you a pro! 

"Well, the cross only required one move…"
Ah, feeling confident, are we? In that case, go ahead and try level 2, where each cross requires two moves. 

Notes:


If you're finding a level hard, you need to go back down one level. 15 seconds of inspection time should always be enough. Some things in life require you to really push yourself to succeed. This is not one of them. The cross is all about practice and repetition and every cross should be easy, because:
When you get your first, say, level 6 cross, you should be thinking: "I haven't seen a cross like this before, but if I did R2, it would be one of those level 5 crosses I'm an expert in." That is the trick for every level. You just have to find a move that will turn your cross into a cross a level lower, because you're already very good at that level or you shouldn't have moved up to this level. 
Each level contains 1,000 random state scrambles.
"Scramble table columns" is just how wide you want the table to be. I've set it to 4 as default, as that gives the best use of screen space on my phone and my tablet. You can change it to whatever you like or set it to 0 if you're fine with just getting the scramble string.


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## Lucas Garron (Apr 8, 2015)

Not bad, the first 8-mover I tried really did take me 8 moves.



net13 said:


> Each level contains 1,000 random state scrambles.


That sounds like it could run out.
Why not generate them on the fly?

If the way you handle this requires generating them ahead of time, could you also check all crosses, to make a color-neutral version?
i.e. each scramble in level N has at least one face with an N-move cross.
I've always wanted to train color neutrality, and it might be nice to motivate myself by saying "if I just look more, there will be a reasonably nice cross on another site".


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## cashis (Apr 8, 2015)

this is great.


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## unsolved (Apr 9, 2015)

net13 said:


> How to use:
> 
> 
> Go here: http://net13.net/Cube/Cross/[1]





I love this and I do 4x4x4 and 5x5x5 only


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## Praetorian (Apr 9, 2015)

Lucas Garron said:


> Not bad, the first 8-mover I tried really did take me 8 moves.
> 
> 
> That sounds like it could run out.
> ...



Do a rotation before each scramble to make a different cross


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## supercavitation (Apr 9, 2015)

Praetorian said:


> Do a rotation before each scramble to make a different cross



I think the point was that he didn't want to know what color the cross would be on, though.


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## net13 (Apr 9, 2015)

Lucas Garron said:


> net13 said:
> 
> 
> > Each level contains 1,000 random state scrambles.
> ...



There are (at least) two ways to do this:

1. You randomly scramble the pieces of the cube not part of the cross. Then you apply X random moves to the cube, making sure they affect at least one cross piece each. Then you run an optimal cross finder to make sure a shorter cross than X isn't possible. I believe this is how csTimer does it with their "easy cross" option, except they skip the last part and often give you easier crosses than you ask for.

The problem with this method is that it doesn't give evenly distributed crosses and so some cross variants will show up a lot more often than they should, so I decided I didn't want to do it this way.

2. You generate completely random scrambles, then run your optimal cross finder on them and start over until you get a cross that requires exactly X moves.

This is IMO by far the best way to do it and so that's how I chose to do it. The problem with this method is that 1, 2, 3 and 8 move crosses are all quite rare (you get one 1 move cross for every 12,672 scrambles). This means that to do it dynamically would be quite slow, especially on mobile platforms.

Also, if there were 10 scrambles, I'm sure many people would recognize earlier scrambles. If there were 100 scrambles, I'm not sure I would ever recognize an earlier scramble. But with 1,000 scrambles? If you go: "Ok, so the scramble is R2 F' R2 B' R2 U2 F R2 U2... wait a minute! I just had this exact scramble like 500 solves ago!", then, well, you should probably move to a higher level and if you're already on level 8, you should probably go learn full ZBLL or something else that takes advantage of your amazing memory. 



Lucas Garron said:


> If the way you handle this requires generating them ahead of time, could you also check all crosses, to make a color-neutral version?
> i.e. each scramble in level N has at least one face with an N-move cross.
> I've always wanted to train color neutrality, and it might be nice to motivate myself by saying "if I just look more, there will be a reasonably nice cross on another site".


That's actually quite easy and a great idea: "There's a four move cross somewhere on this cube, I just have to find it." I'll think about it. 

Also, could you do something so you don't have to moderate all my posts? I promise I'm not a spammer.  I made a tiny edit to the post above and now the entire post has disappeared, probably because you have to moderate it again.


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## PJKCuber (Apr 9, 2015)

Innovative


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## Berd (Apr 9, 2015)

Cool!


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## Nilsibert (Apr 9, 2015)

This is awesome, exactly what I need. Cross to F2L is what usually messes up my solves .


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## TheOneOnTheLeft (Apr 9, 2015)

net13 said:


> There are (at least) two ways to do this:
> 
> 1. You randomly scramble the pieces of the cube not part of the cross. Then you apply X random moves to the cube, making sure they affect at least one cross piece each. Then you run an optimal cross finder to make sure a shorter cross than X isn't possible. I believe this is how csTimer does it with their "easy cross" option, except they skip the last part and often give you easier crosses than you ask for.
> 
> ...



For the 1, 2 and 3 move crosses, why not generate the random scramble, find the optimal cross, and then apply some of the moves of the optimal cross until it leaves a cross that takes the desired number of moves? For example, if you generated a scramble with a 5 move optimal cross, then you can apply the first 4 moves of that solution to produce a 1 move cross scramble. If there are multiple optimal crosses then just randomly choose one to apply moves from. You can then generate a scramble for that position.


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## net13 (Apr 9, 2015)

You're right. I just like that it's the same method for all levels.


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## guysensei1 (Apr 9, 2015)

TheOneOnTheLeft said:


> . You can then generate a scramble for that position.



You could also just append the partial cross solution to the end of the original scramble.


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## net13 (Apr 9, 2015)

I think then it would become a game of memorizing the last moves of the scramble instead of trying to find the cross.


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## ottozing (Apr 9, 2015)

Any particular reason for the diagram notation? IMO it's not needed since this tool is geared toward more advanced/intermediate solvers, who are presumable very comfortable with standard notation. Other than that, I definitely like the concept, although I don't think I'll be using it myself since cross to F2L is one of my much stronger points


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## net13 (Apr 9, 2015)

I actually made it for beginners, since I doubt people like yourself will have much use for it.  I even put "for beginners" in the thread title but a moderator renamed it when he moved it to the correct forum. 

If anyone doesn't like the cute images and still want to use it, they can just set "Scramble table colums" to 0 and that will just give them the scramble string.


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## DJAlex (Apr 9, 2015)

Thanks I'm going to be using this a lot.


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## Randomno (Apr 9, 2015)

net13 said:


> I actually made it for beginners, since I doubt people like yourself will have much use for it.  I even put "for beginners" in the thread title but a moderator renamed it when he moved it to the correct forum.



It's pretty inexcusable for someone not to know SiGN by the time they start F2L.


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## Rune (Apr 24, 2015)

I have solved 30 cubes at level 8 ("requires 8 moves"): 9 required 8 moves, 20 7 moves, (one 1 move).
For column 0 it would be desirable to show the end result of the scrambling (for controlling yourself).
Is it hard to get a choice of colour at the top when scrambling (not only W/Y)?


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## net13 (Apr 24, 2015)

Rune said:


> I have solved 30 cubes at level 8 ("requires 8 moves"): 9 required 8 moves, 20 7 moves, (one 1 move).


Are you counting slice moves as one move? Because that's supposed to count as 2.  The one requiring just one move I don't understand at all. I'm pretty sure that's not possible, unless it's scramble for white cross and you can solve something like blue in one move. 



Rune said:


> For level 0 it would be desirable to show the end result of the scrambling (for controlling yourself).


What's level 0? 



Rune said:


> Is it hard to get a choice of colour at the top when scrambling (not only W/Y)?


No, but does it matter much? I find that even if the colors are different, it's still pretty easy to look at the image and see if you messed up.


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## Rune (Apr 24, 2015)

1. Could you give me two 8-movers?
2. I had changed "level" to "column".
3. I start with red on top and it isn´t too simple to determine if my scramble concises with the given one.


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## net13 (Apr 24, 2015)

1. Sure, I'll just grab two from the page (cross on top):

D R2 D R2 D2 F2 D' R2 F2 D B2 L R' U' F2 D' F D' B' R'
D2 B L2 F U2 L2 F2 B' D2 L2 F' U R' D F R D L' R D

I haven't verified these are actually 8 move crosses, but you're the first person who has claimed to be able to solve them in 7 moves or less, as long as we count slice moves as two moves. 

2. Ah, alright, yeah, someone else asked for that too and it's pretty easy. I'll think about it. 

3. I understand, I'll see what I can do.


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## Rune (Apr 24, 2015)

You could have helped me by showing the end result. I´ve scrambled three cubes with different outcomes. I´m looking for a fourth.

Edit:
I´ve found two cubes that have the same scramble. Solution: L D B´ L R2 U2 B´


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## Petro Leum (Apr 24, 2015)

Can someone do this for ZZ? i think theres an easy EOLine scrambler somewhere, one could probably take that


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## Rune (Apr 24, 2015)

The second one: F L´ B´ U L´ D F2


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## Cvaughn55 (Jul 18, 2018)

I noticed that this website was down, so I made a modified version of the original since the user who made it hasn't been active. I removed the orientation and table columns since i didnt think many people working on their cross to F2L transition need help with sign notation. You can access it here https://cvaughn55.github.io/C2F2L/ and if net13 wants me to remove this i gladly will.


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## LightFlame_ (Jul 19, 2018)

net13 said:


> *[CFOP] A tool to practice cross and transition to F2L*
> 
> How to use:
> 
> ...


this is, to say the least, genius. im surprised i hadn't found it before.


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## Cubetastic5 (Jul 19, 2018)

The link seems to be broken - if I visit the site, it says server not found. Are you sure the link is still http://net13.net/Cube/Cross?


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## LightFlame_ (Jul 19, 2018)

Cubetastic5 said:


> The link seems to be broken - if I visit the site, it says server not found. Are you sure the link is still http://net13.net/Cube/Cross?


If you look up, you can see another website that does the exact same thing


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## Cvaughn55 (Jul 20, 2018)

I made some updates to my version of the site here.

Made color scheme more friendly on the eyes
Made the site properly scale on mobile devices.
If you Install Google Chrome Dev on Android you can install the site as an android app to use in fullscreen mode and offline.






Hope you guys enjoy. Also this is just hosted on github, so it shouldnt randomly go down like OG one did from net13


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## Cubetastic5 (Jul 20, 2018)

Cvaughn55 said:


> I made some updates to my version of the site here.
> 
> Made color scheme more friendly on the eyes
> Made the site properly scale on mobile devices.
> ...


I actually liked the dark theme better... could you at least make an optional dark theme? Dark themes are really good! And why only on android? If you're using a service worker, it should work on all devices, right? And on android it should work on firefox as well, and also on safari in iOS. Are you sure it's only for android?

Update: Just tried it, it works on Linux.


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## Cvaughn55 (Jul 20, 2018)

Cubetastic5 said:


> I actually liked the dark theme better... could you at least make an optional dark theme? Dark themes are really good! And why only on android? If you're using a service worker, it should work on all devices, right? And on android it should work on firefox as well, and also on safari in iOS. Are you sure it's only for android?
> 
> Update: Just tried it, it works on Linux.


It should work on all devices, but with chrome dev on android it actually installs it as an apk when adding to homescreen instead of other browsers where it makes a fullscreen shortcut. Also I won't be at my pc today, but when I get home tonight I can add a dark theme .


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## Cvaughn55 (Jul 21, 2018)

@Cubetastic5 I updated the site to now have the Default light theme with the red, and a Dark theme which is all grey. Also added 3 Color themes that work on both light and dark. To use them just click on the double colored square for light/dark swap then any of the colors to choose a color. I also am going to try and implement a thing to remember the last selected theme soon.


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## Cubetastic5 (Jul 21, 2018)

@Cvaughn55 that's amazing! Thanks a lot. I find the site really useful! Also, see if you can use local storage or something to store the last selected value for the level select menu.


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## Pecinajunior (Jul 21, 2018)

I can't open it, it tells me that the server wasn't find, is that problem of my PC/ethernet connection or the web? I'm using Firefox for Ubuntu


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## Cubetastic5 (Jul 21, 2018)

Pecinajunior said:


> I can't open it, it tells me that the server wasn't find, is that problem of my PC/ethernet connection or the web? I'm using Firefox for Ubuntu


The site is down, but you can find another site that does the exact same thing a few messages above.


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## aybuck37 (Jul 21, 2018)

Cvaughn55 said:


> I made some updates to my version of the site here.
> 
> Made color scheme more friendly on the eyes
> Made the site properly scale on mobile devices.
> ...


wow my favorite website got an update!


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## teh yoshi (Jul 22, 2018)

Man, where has this been all my (few months of my cubing) life? Thanks so much for this! I'm really motivated to get practicing more now.


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## LightFlame_ (Jul 22, 2018)

@Cvaughn55 can you make the site an app for ios? im going on a trip and itd be great if i could practice on the place, where there is no wifi


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## Cvaughn55 (Jul 23, 2018)

LightFlame_ said:


> @Cvaughn55 can you make the site an app for ios? im going on a trip and itd be great if i could practice on the place, where there is no wifi


@LightFlame_ I just borrowed a friends IOS device, and when you go into safari you can add the site to home screen and with my short testing time I was able to load the homescreen shortcut while in airplane mode, so it should work offline. Just has some scaling issues on IOS so you have to scroll up and down to get it to see everything


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## Cubetastic5 (Jul 23, 2018)

LightFlame_ said:


> @Cvaughn55 can you make the site an app for ios? im going on a trip and itd be great if i could practice on the place, where there is no wifi


Um... try this: go to the site in safari, and click the share icon:





then, scroll and select "Add to homescreen". It should work like a normal app.
Note: This _won't_ work for all websites, but it'll work for this one.


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## LightFlame_ (Jul 23, 2018)

It works!! Thanks everybody!


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