Rubik's Cube, but some turns are ILLEGAL

every time you solve a Rubik's Cube you're almost guaranteed to turn all six sides at least once if you start with the white cross like me you probably turn the yellow side more than anything the white side only a couple of times per solve and the other four colors land somewhere in between that's why today I want to find out what it's like to solve Rubik's Cube if you limit the number of sides that you're allowed to turn believe it or not any Rubik's Cube scramble can be solved by just turning five out of the six sides but how much more difficult does that make the solving process and what if you limit yourself to just four or three or two today we're going to answer are all of those questions starting with the first level of difficulty where just one side is illegal to turn and we're going to enforce that using a screwdriver I'm just going to pop the center cap off here and then tighten this screw down until the white side doesn't want to turn anymore there we go I'll also add a little black sticker here just to remind us that turning this side is now prohibited as you can see it doesn't want to turn at all but the other sides around it do turn just fine let's get started so looking at this cross case here what I would normally do to solve it is put in these three pieces first kind of like this and then I would do a move to align the cross and then solve the last one but as you can see that D move is not possible right now so instead we're going to have to do it the beginner way of basically just putting in the cross pieces one at a time and then moving the next one onto the yellow side putting it in next one putting it in and putting it in until the cross is solved so that was all very tedious but fortunately after that first step of making the cross there's very few reasons that you would ever need to turn the white side again one reason I might do it during f2l is if I had a case like this where the edge piece were already perfectly in what I would do is take this corner piece do a dmve to bring that slot over put the corner piece in and then bring the slot back that's called Keyhole it's a very useful intermediate f2l trick but instead we're just going to have to do it the boring way instead and this last one should be nice and easy to finish up too now as annoying as this o is I don't think it requires turning the white side at all most 's don't you do have to pay attention though because as soon as you start doing middle layer moves like this algorithm requires that white side starts to move around and all of a sudden it's not D moves that are prohibited anymore it might be F moves or U moves for example in fact I actually know an algorithm for this exact up perm that starts with M2 U so in this case that wouldn't be allowed at all because we'd be turning the white side instead we have to do the clearly Superior Ru version and there we go as easy as that the cube was solved by turning just five sides there were a few minor difficulties along the way but nothing that couldn't be overcome very quickly so now it's time to make another site illegal how about Green Let's tighten this one up there we go and just to make sure let's add a big piece of tape all the way across here to make sure we absolutely can't turn either of these two sides all right now as we start to scramble up this Cube you might notice one thing that's a little bit funny there's one Edge piece right here that's completely trapped there's no way to turn it and move it from where it is without turning either the white or the green side and so that's why it's actually impossible to pick up any old scrambled Rubik's Cube and solve it by only turning four sides or any less than four unless that edge piece is already where it needs to be there's no way it's magically going to get there unless you can turn the two sides next to it but good thing for us that means we already have one cross piece solved so we can go ahead and move on to the next one over here we can do the this orange one like this and then this red one over here I would normally solve by doing D RP Prime D Prime but instead we have to take it out and then put it all the way over here to get it in but from now on f2l should go nice and smoothly right oh wait a minute these two pieces that I just got into position to pair up into the back slot I can't pair them up without doing an R Prime right there so how do we work around this well what I think we can do is instead of inserting into this slot instead we can insert into the slot next to it like that and then we can just take it back out again and insert it into where it needs to go except that now that I've paired it up like this I still need to turn the green side to put it in even if I try and do a sledgehammer that still requires the green side so instead what I think we have to do is put it back into a different slot and then instead of taking it out with an L move like this we want to take it out with an R move this way we can insert it with an R move over here which doesn't require the green side at all so that was a nice little workaround it definitely takes a bit of planning ahead and definitely steps up the difficulty a little bit but for the most part the rest of these f2l pairs should be pretty easy for this one right here I would normally do sexy move three times so r u r Prime U Prime over and over again but since I can't do an R move I'm instead going to have to do the mirror of that by doing it with L moves over here and now since most last layer algorithms require R U and F moves I'm just going to get this green s out of the way by putting it on the back and then hopefully this algorithm will be doable which it looks like it is but this AP per on the other hand doesn't look like it's going to be easy normally I would solve it like this by rotating and then doing R2D2 but obviously we can't do a d2 move right now so what if we rotate it back to where where it was and try that again uh now we can't even do the R2 move but now what if we do another U Move and then try and do the algorithm over here so R2D2 that now works r u but we can't do the U so we have to very carefully undo all of those Our Only Hope left is that maybe this last rotation will work so R2D2 r u r Prime oh my gosh it worked so we just got very lucky that a required all four sides of the cube except for these two and only when it was in that exact orientation now before we move on and try and restrict three sides at a time I want to know what would happen if you try and restrict not just two adjacent sides but two opposite sides so you're not allowed to turn white or yellow I have a feeling it'll be a lot more difficult but I've never tried it before so I have no idea so I'm just going to free this green side real quick and then restrict the yellow side and we'll see what happens okay this cube is really not happy with me right now tightening these two sides really seems to be restricting the other four sides but I think we can manage so let's scramble this Cube up and see what it's like to solve it now as I mentioned at the start of the video when you're doing a solve on white cross the side that you turn the most often is yellow it kind of makes sense because almost every f2l pair o algorithm and pl algorithm all require doing some U moves and so I think for the sake of my sanity it might actually be easier to start with a different cross color it might be a little bit more confusing but I think it'll be worth it in the end so let's go with how about Green Cross fortunately we do have a lot of moves available to us that are very useful for making this cross so we can go ahe and get these first three pieces in here and where's the last one oh it's over here unfortunately we can't just do a quick R2 move right here to put it in but what we can do is move the cross out of the way move the piece out of the way do an R2 move and then put the cross back and there we go now it's solved now besides these F2 pairs being impossible for me to recognize I think this shouldn't be too much more difficult than it was last time there are definitely some cases where I'd like to be able to turn these two sides for example right here if I were to just do an L Prime move I would pair these two pieces up and be able to insert them but instead I guess I just have to do it the fancy way by rotating and then doing these moves like this now if you try this challenge out yourself you might find that all the f2l pairs seem to go in so easily when you have white and yellow in the front and back like this whereas if you try and rotate and have them on the sides there's seemingly no way to insert any f2l pairs at all like what would you even do from this angle you can't do a sledgehammer whereas if you just rotate it this way and have this on the front and back it's always super easy to get them in and if you've ever learned ZZ you'll know exactly why this is It's because all the edges on the cube are already oriented what does it mean for an edge to be oriented it means you can get it into its correct position without doing any F or B moves and so because we scrambled this cube without doing any F orb moves we automatically got all our edges oriented which means we automatically get all the easiest f2l cases which don't require rotations or F moves and once we get to the last layer we know that all of our cross edges will already be oriented giving us an easier oil case so all in all this challenge just made our lives a little bit easier but wait a minute this o isn't possible it requires basically doing an f move by turning the white side right here so how do we solve this well my fallback is to just use that one beginner's method where you do a bunch of soones over and over again so like this anti-s and there we go now that we're on to PLL a lot of the cases would be really tricky to do without any F moves but we just happened to get lucky here with a up perm that we can do with just r&u moves and so much like the last challenge we did where this Edge piece was stuck in place this challenge also drastically restricts the number of different ways that you can scramble the cube it just does so in a much different way than the other one did and so in this case that made it easier in some ways but also harder in some ways okay what's next I want to restrict three sides so that there's only three left over that you can turn there's actually a couple different ways that you can do that so let's just try out both of them the first one I think we're going to find is very similar to what we just did but I want to try it again just to be sure so just like last time there's two opposite sides that we can't turn but we also now can't turn the bottom either we're only allowed to do our U and L moves and so what I'm very quickly finding out is the more sides I restrict the less it feels like I'm actually scrambling the puzzle obviously we have two Edge pieces that are completely trapped but like last time we're also leaving all the edges oriented which makes our lives a lot easier during most to the solve so I'm just going to start by making the white cross as usual if you were actually doing ZZ you would wait to put in these two Edge pieces until you absolutely needed them but I'm too lazy to do that and now you can see if we just resist the urge to ever rotate the cube we can find really efficient solutions to all of the f2l cases now some of them like this one right here are going to really annoy me that we can't just rotate and do beginners method so instead we had to do something crazy like this and even if it's more moves it still feels really nice only having to do r&u moves and never rotate now fortunately this time we got no l case that that's really easy to do with just rnu moves okay now here's the hard part as I suspected last time we just got really lucky by getting a upm and so now we have to figure out how to do a complex PL like a g perm without doing any F or D moves now I doubt there even exists a g perm algorithm we can do here so we're definitely going to have to do T look and the only PL that I can think of that only requires these three moves and that swaps these two corners around is my ja perm which goes like this and there we go now we got all the corners solved and we have a nice easy uerm to finish things off now if we had dead got really unlucky and had to swap two opposite Corners we could just do that J perm twice in two different positions or I think one of my n perms actually will work too yeah okay that's actually really cool anyway get it it's time to move on to the other way that you can restrict three sides of turning which is when you have three adjacent centers so let me go ahead and modify this tape real quick there we go white Side Green side and orange side all illegal let's see what happens this time I have a feeling the last layer isn't going to be as difficult because we can do Ru and F moves very easily but I think F12 might be getting a little bit more challenging so we now have two pieces of our white cross and a full F12 pair that are locked in place and so it should be very easy to get our white cross and lucky us it's an xross so let's go ahead and begin with our first f2l pair here so let's get this one in here that wasn't too bad and that gave us another free f2l pair so it's as easy as just sticking that in where it needs to go oh wait a minute it's fine let's just do a sledgehammer to get it in oh wait a minute so much like one of those previous solves it's now very difficult to get some of these f2l pairs in in and I think the best thing to do is to fall back on our previous strategy by inserting this into the wrong f2l pair we're going to have to mess up this one that we already made but oh well and then taking it out with the opposite move so an L move here and then that lets us insert it where we want it like that and so I'm going to refrain from inserting this middle F 12 pair again because as we just found out it's a very useful slot to have open and so instead we have to work with this one over here which we can do just like this and then ah we can't get it in again and so once again we just put it into the wrong slot take it out with the opposite move and then we can put it into the slot that we want to and now we can finally do the middle F2 pair using basically whatever moves we want to so just beginner method there now moving on to O we have R U and F available so we could always fall back on The Beginner's method algorithms and just do this to get the yellow cross then do soon a bunch of times but in this case we got lucky so it was just one easy algorithm and then yeah most plls including this one can be done with just run andf moves so are pretty much Home Free there we go worst case you could always just do J perms to get the corners and then U perms to get the edges easy now the reason I know so much about solving with this restriction in particular is that it's exactly the same concept as 1/2 of a Siamese Cube if you think about it this has the exact same restriction you're allowed to turn these three sides but not the three other sides so every time you solve the Siamese cubes you're literally just doing this twice which is why I have so much experience with it so now let's move on to restricting four sides of the puzzle and seeing what it's like with just two sides remaining there we go oh wait a minute that's not going to be very much fun is it it's uh 1X 1x3 ah there we go go that's better now I'm not convinced this one is going to be much of a challenge either but we might as well try it for the sake of completeness I think it's basically going to be like when we had three centers disallowed in a u- shape except now we have this whole side disallowed too so it's just going to be a slightly shorter version of that solve anyway let's get started uh white cross that was easy now for our first f2l pair we can do something like this to get that in there and our second f2l pair should be nice and easy too just like that now once again we're guaranteed to have all these edges oriented so we could just do a bunch of soones or if we're lucky enough to get an algorithm that we can actually do with Ru moves we can do that as well and now since it's impossible to do any plos that require anything but R andu moves it's impossible to get any of those poow either we're never going to have two Corner swap for example it's all just going to be U perms H perms or Z perms which all can be done very easily just by doing one or more ups and so interestingly as we kept on increasing the number of sides that we restricted the challenges kept getting more and more difficult up to a point where we had so many pieces that were just bandaged together that the rest of the cube really had so little options that it actually became easier than a normal Rubik's Cube I think the one where we just had two opposite centers restricted was my favorite because we still had all the pieces in play and it had some unique challenges and benefits I'd never actually tried that one before that one was probably the most difficult although the Siamese Cube Style version was a little bit tricky too but I'm glad we tried out all the unique combinations of different sides that you can restrict to see the unique challenges of each one wait a minute we haven't tried all of them yet what happens if you restrict five sides that's totally a puzzle isn't it yeah it's a 1ex one by two well I'm glad we were able to solve that one for the sake of completion and oh actually I just thought of one more all six sides restricted bet you can't solve that one huh anyway I hope you all enjoyed this fun challenge video let me know if you want to see more like it and I'll see you guys next time [Music]

Channel: Z3Cubing

Views: 96,643

Keywords: rubiks cube, rubiks, cube, cubing, cubes, puzzle, puzzle cube, magic puzzle, magic cube

Id: PE16NJokJac

Length: 13min 54sec (834 seconds)

Published: Sat May 25 2024