It's Easter! I have a whole day to do stuff like write my first cubing tutorial since before Christmas! Today's tutorial is a two-fer, too! May I introduce to you two very interesting puzzles that are actually exactly the same puzzle: the Super Ivy Cube (front, at left) and the Rex Cube (front right).
Joining them in the back row, from left, are our old friends, the
Redi Cube, the
Dino Cube, the
Skewb and the
Ivy Cube – all variations on the theme of corner-turning cube puzzles.
I'm not mad that I bought both of them only to have them turn out to be the same puzzle. In fact, I already owned, and knew how to solve the Super Ivy Cube, and knew the Rex Cube was the same puzzle, when I bought the Rex. For some reason, I just couldn't resist. There's something interesting about how superficially different they are. They're both fun to play with, though my Super Ivy Cube (in my opinion) looks prettier, feels better in the hands, turns more smoothly and has that certain
je ne sais quoi that comes with little tiny magnets inside, helping snap the layers in place between moves. Rex is just a touch more creaky, a little more flimsy-feeling and a bit more prone to lock layers, but not so much that it isn't fun to mess with. Sometimes I'll scramble both of them at the same time, just to have more time messing with this unique solution.
You might have spotted the apparent connection between the O.G. Ivy Cube, shown below at front, and the Super Ivy Cube.
Yes, they both have that geometric distinction of turning like portions of a sphere inscribed inside a cube. However, the Ivy Cube, a.k.a. the Eye Cube, has this drawback: You can only turn it around four of its corners. While this makes solving the Ivy Cube ludicrously easy – like, seriously, just play with it and it'll practically solve itself – it also takes away from the intrepid puzzler's overall satisfaction. You want a toy that'll turn the same way whichever way you hold it. You want a cube that turns like the Ivy Cube, but from all eight corners. Well, that's what's super about the Super Ivy Cube, and it's what royal about the Rex Cube.
How many ways can the Super Ivy and Rex cubes turn? Let's count the ways. And how convenient that there are two of them! In the photos that follow, I took advantage of the fact that they're essentially the same puzzle, using the Super Ivy Cube to demonstrate clockwise turns and the Rex Cube to show "prime," or counterclockwise moves – if the lighting permits you to make out the colors. So here, they are, starting with white at "up," green at "front" and red at "right," theoretically – though I find it helpful in these corner-turning critters to hold the cube so that you're facing the edge between front and right. With that settled, here are
F and F' (I'm still calling it F prime, though some cube-tutorial vloggers seem to be using the notation "Fi" and calling it "eff eye" these days).
Here, shot from a side angle so you can see it, are the moves
B and B', at the corner diagonally opposite F. Remember, the clockwise vs. "prime" designation is based on the point of view directly facing that side.
Here, shot from above because it's hard to see from the front, are the moves
U and U'.
And here, awkwardly, are
D and D' – you know, diagonally opposite from U/U'.
Here are
R and R' – counterintuitively lower-layer moves:
Here, again shot from above, are the top-layer moves that my trusted Redi Cube scramble algorithm calls
UR and UR':
Here, back on the lower level, are
L and L':
And here, on the upper level again, are
UL and UL':
That's an insane scramble notation, but the good news is, you can pretty much forget about it once you've got the cube scrambled. But now we come to an important notation issue I haven't fully wrapped my mind around. Starting from our standard, white-up and green-front position, here are some moves that don't involve twisting any part of the cube. First, here's the move known in standard notation as
x, which is basically like an "R" move except you're rotating the whole cube. Sorry, I neglected to film an x' move; and of course, a 180-degree turn would be x2.
The existence of an x move practcially implies that of a
y move, which is basically a whole-cube rotation in the direction of a U move:
And finally, here's the
z move, i.e. a whole-cube rotation in the direction of an F move:
What bakes my biscuit is the fact that there's a cube rotation, frequently occuring in the Super Ivy/Rex Cube solution, that defies standard notation. Maybe. It goes like this, viewed edge-on:
Unlike the x, y and z moves, this rotation leaves you looking at the same three sides, but with a different one on top. You're basically rotating it around the vertex at top front. It's important, at a certain point in an algorithm you're going to do many, many times while solving these two puzzles, that you turn it exactly this way. I guess it comes closest to being a z move, possibly modified for holding an edge at front; or perhaps it's a simultaneous y and z move. But the important thing is that you keep the same vertex at front and simply rotate the three sides around it, 1/3 turn clockwise. I can't find a notation symbol for this turn anywhere, but in order to keep things concise, I'm going to suggest that we call it
w for this tutorial. Don't worry about w' or w2 (shudder; too soon after tax time!) – you'll only need the basic move for these two puzzles. And you'll need it a lot.
There are basically
three steps in this solution: (1) Solve the edges. (2) Solve the centers. (3) Solve the petals, or leaves, if you choose to call them that. I prefer "petals," personally. Each step has its own algorithm, one of which you may only need to do once or twice while you'll be repeating the others all over the place. All three of the algorithms are variants on the pattern "up, up, down, down," alternating between right and left. However, they don't
always alternate R-L-R-L; sometimes it's L-R-L-R. And also, which corners you're twisting aren't the same in all of the "up-up-down-down" patterns. So pay attention!
Here, for example, is an "up-up-down-down" pattern, starting on the right, that twists the top-back corners. I shot a series of pictures to illustrate it, just so you know what I mean when we get to that step – which is actually Step 1. Observe:
It's important to remember: to rotate the top-layer edge pieces you have to do this "up-up-down-down" pattern on the top back corners, R-L-R-L. But please note three-and-a-half things: (1) Each rep of this algorithm will cycle the three edges at right, back and left one spot counterclockwise, while leaving the front edge untouched. So, in the example pictures, the white-orange edge moved from the back to the left; green-white moved from left to right; and blue-white moved from the right to the back. (1.5) For a clockwise cycle, start the algorithm on the left. Or just keep doing the same three-cycle until you get the result you want. (2) A couple of the edges flip during this process, putting the white side of the edge facing sideways. Don't panic; by the time you've cycled the pieces into their correct positions, they'll all be flipped right-side-up. (3) This is what I like to call a "dirty" move, meaning that it doesn't just cycle those three edges, but it also scrambles some centers and petals. It's a good argument for doing the three steps of this solution in the correct order: Every time you run the edge algorithm, it makes a mess that you have to clean up.
Now, let's start from the very beginning and try those three steps. Here's the Super Ivy Cube again, in starting position. Rex has moved to the cheering section, since it doesn't have anything to show you apart from the exact same moves.
Let's cannibalize the Redi Cube scrambler from scramble.cubing.net, which i keep bookmarked on my phone. It's as close as you can get to a scrambler for the Super Ivy Cube, as far as I know. The results aren't exactly as advertised, but that may be due to operator error:
STEP 1: SOLVE THE EDGES. Pick one side to start with, and make sure the edges are in the correct order going all the way around. I almost always start with white, and it's helpful to remember that the adjacent sides in order, counterclockwise, are B-O-G-R, blue-orange-green-red. In these first two pictures, I found the white-orange side directly opposite blue-white on the top layer. I did what amounts to a UR' move to dial it in.
Next, I found the green-white edge and dialed it in. Then I dialed it out again, spotting an opportunity to unite it with the red-white edge, here shown facing away from it on the opposite edge, at right. Then I dialed red-white in next to green:
It's conventient if you can position those two edges so that, with a single twist, you can dial them into place on the same side as the other two white edges, like so:
If you find yourself with an edge in the wrong spot, breaking up the B-O-G-R order, just dial it out and put it back in where it belongs.
Moving on, put your first side with solved edges (i.e., white) at bottom and start dialing in the edges between the middle-layer sides, like the red-green edge shown at front.
And this orange-blue edge:
In this last photo above, perhaps you can see the green edge at back right; actually, a green-orange edge, which needs to move all the way to the front left. I think the next few pictures are my attempt to show the moves involved in doing this.
I had to break that blue-orange edge to do that, so here's me fixing it again.
But that maneuver left the final side edge, blue-red, on the top layer. So, first I dialed blue-orange out of the way (I think it went to the front left):
Then I rotated that blue-red edge into place, before dialing orange-blue back in:
The last bit of Step 1, where you do that three-cycle with those top-layer edges, wasn't necessary to my example solve. See how all the yellow edges came right into place with that last side edge? That had never heppened before in my (not very extensive) experience with the Super Ivy Cube. But I decided not to mess with it. So I guess it's a good thing I demonstrated that last-three-edges algorithm earlier. Eh?
STEP 2: SOLVE THE CENTERS. Start by checking for any sides whose centers are already in place (i.e. surrounded by their color's edges). Looky here, I had green and red in place already!
Next, look for an oportunity to solve a center on an adjacent side. The idea is to put together three sides with solved centers around a common vertex. For example, the white side in this picture is adjacent to both red and green; and there's a white center right next to it, on the blue side.
Unfortunately, there's no way to just swap the two centers; but you can do a three-cycle, either clockwise or counterclockwise. Looking at the three sides like this, to insert the white center into the side with the white edges, without breaking any of the edges you've solved so far, you could do the "up-up-down-down" algorithm, times two, turning the vertices at top-right and top-left while viewing the cube edge-on. So, that's a "front" up-up-down-down, as opposed to the "back" up-up-down-down you learned for the edge algorithm. And it's multiplied by two. And it starts on the right, for a clockwise cycle of these three centers; for a counterclockwise cycle, you'd start on the left. Behold:
The result: You now hoave three adjacent sides, surrounding a common vertex, with centers solved.
The reason this is important is that it sets up a three-cycle between the remaining three sides. Note how a counterclockwise cycle will put all three of these centers where they need to go:
Here's that center-cycle algorithm again, starting from the left:
STEP 3: SOLVE THE PETALS. Or leaves, if you prefer. Chose a side to start with, maybe looking for one that already has some petals solved. In my demo solve, I didn't bother with this; I just decided, what the hell! Let's solve red first! – even though none of the red petals were in place. Here's the sitch:
I see an opportunity here, with that red petal in the upper right corner of the white side. You'll understand what I mean in a bit. So, to prepare for our third and most frequently-used algorithm, I twist that white corner with the red petal up onto the red side, where it's diagonally opposite a white petal. I'm going to swap them, don'tcha know.
Here I've rotated the cube to the position where I'm going to start the petal-swap algorithm. Notice that the white-red business is at right, with the two petals to be swapped (white and red) lined up from northwest to southeast.
Also, brace yourself: the move that's about to happen is ALSO going to swap the two petals at front (the blue side) running from northeast to southwest. Just those two pairs; everything else will remain exactly the same. Because this is such a "clean" algorithm, it's handy to keep for last. But remember which pairs of pieces are going to be swapped; this will lead to some strategic decisions, later on.
Now, the algorithm is as follows, keeping this same vertex in front throughout: UR UL' UR' UL w UL' UR UL UR'. In other words, up-up-down-down starting on the right; that weird whole-cube turn I discussed way up above; then up-up-down-down starting on the left. Here it is, step by step:
Careful, now! Don't forget to undo that setup move you did before, to put the red and white petals opposite each other.
The result, as you can see above, is that the two petals have swapped places, and are now on their correct sides. Also, the red and blue petals on the blue side have switched places, which is nothing to worry about just yet. Notice that, due to the way the cube turns, the positions of the petals you can swap between adjacent sides are northwest on the one side and northeast on the other. So, in this example, you can swap the red petal on the blue side (northeast) with the white petal on the red side (northwest).
First, do the preparatory move (in this case an F') to dial the two pieces into opposition:
Then, rotate the cube so the two pieces being swapped are at right, lined up northwest to southeast. The two petals that will swap places at front both happen to be green, so you won't be mixing anything up that you don't want to.
Let's just skip past all that up-up-down-down stuff, which I've demonstrated plenty above. The immediate result shows the red and white petals at right have swapped places.
After undoing the setup move, you can now appreciate that the red side has two petals in place.
Now my thumb is going to make a cameo appearance. Here's the next red petal I'd like to try moving onto the red side.
But because it's in a southwesterly position, here's what happens when you try to dial the red corner with the blue petal up on top:
See the problem? That red petal got pushed out of the way onto the front side, meaning that if you tried the petal-swap algorithm now, you'd just be swapping a yellow petal for the blue. Here's what to do: Perform a petal swap, with no setup move, simply to swap the red and yellow petals on the green side. Note, again, that the two petals swapping places on the orange side are both green, canceling out any collateral damage. Before and after:
Flipped back around, you can now see conditions more favorable for swapping that blue petal on the red side with the red petal on the green side.
Once again, here's that setup move:
Rotating the cube to put those two petals on the right side at NW and SE, we find those same two green petals on the orange side lined up for a similar swap:
One petal-swap algorithm later:
When you undo the setup move, again you find the red side one petal closer to being solved.
Finally, the last red petal is in place for a setup move, swapping algorithm and reverse setup move versus the orange petal on the adjacent side:
Red side solved! Now you can move on to some of the other sides. It doesn't really matter what order you do them in; only take advantage of opportunities, as you can, to build on sides that are already partially solved, and try to make sure the last two sides are adjacent to each other. Here is the gruelling saga of my example solve, as briefly as possible, illustrating pretty much everything this puzzle can throw at you. First, I wanted to bring this blue petal down from the orange side:
Now where's that last blue petal? Oh. Way over on the opposite side of the cube. 'Coz green is as far from blue as you can get, in case you're joining the program late.
This calls for not one, but two setup moves: first, to bring the blue petal from the far side of the cube onto a layer adjacent to blue; then, to dial the white petal from the blue side into contention with it. Don't forget that you now have two setup moves to undo!
Then, just do the petal swap algorithm and restore the setup moves. "Just!"
Now that you've solved red and blue, why not go for a side adjacent to both? That'll guarantee that the last two sides don't end up on opposite sides of the cube. Also, white already has one petal solved, which is almost the first good luck I've had since the top edges solved themselves.
Again, it's a two-setup-move problem. First, you need to dial that white petal off the green side to put it in a position to swap onto white; then you dial an orange petal into opposition with it.
Once the petal-swap algorithm is done, you have to remember do undo the two setup moves in reverse order.
Then you're dismayed to discover that the remaining two white petals are both on the yellow side; i.e. all the way around the cube. Why did solving white next seem like such a good idea?
Prep move one: dial those white petals onto a side adjacent to white. Oh, never mind. Before you can swap them in, you have to edge-swap both pairs of petals on the white side to put the non-white ones in position.
So, undo that setup move and get petal-swapping, within the white side. Here's swap no. 1 (green vs. white):
You have to rotate the cube to put the other pair of petals (orange and white) in position for a petal-swap algorithm. The upside of putting this swap up against an already-solved side (red) is that swapping the two red petals won't break anything.
Now, at last, you can go back to that setup move from the yellow side that you had to cancel earlier; then a second setup move to put orange opposite it (sorry about the focus), and you're off.
One petal-swap later, and edges all restored, you can now set up for the last petal-swap to solve white. Unfortunately, in this instance, you can't escape the necessity of breaking a petal you've already solved, due to how the setup moves put a white petal in contention on the front side. Believe me, I looked for a way to avoid a situation like this, but it isn't always possible.
That still left me one petal away from solving white. Yeah, that can happen. And this demo solve seems to be trying to demonstrate just about everything that can happen.
Now you can finally solve the white side. I shot a bunch of pictures of this step, but they were all out of focus except before-and-after:
I wish I didn't have to show you this out-of-focus picture, but it establishes what's left of the puzzle after finishing the first three sides.
I guess I decided to swap an orange petal on the yellow side for a yellow petal on the orange side. Here's the setup, after the petal-swap and reverse-setup:
Apparently, the next petal-swap I wanted to go for involved the orange petal at the NW corner of the yellow side (right) and the green petal at SW of orange (front). First, with no setup move, I would have to flip both petals to the opposite corner of its starting side. Luckily, they lined up just right for me to do both swaps at once.
Then, with a prep move to put the two petals in opposition, I took advantage of the fact that at this stage of the game, you can't mess up a completely solved side:
At last, we're down to the last two sides – yellow and green. The first petal swap is simple and classic:
After another apology for focus, the final petal-swap required one of the petals to flip to the other corner of its eye:
Then the usual setup move, petal-flip algorithm (which, again, can't hurt the solved blue side) and, to complete the solve, undoing that last setup move. The after-photo of which is also out of focus, but you don't need it. You can tell what's going to happen, can't you?
I tried to learn how to solve the Super Ivy Cube without help, but I found it frustrating. I then consulted a bunch of online tutorials and found some of them very unhelpful. "Turn it like this," the guy says. Like what again? What did you just do? I watched them over and over and never heard any explanation of what they were doing. To some degree, I figured out how to imitate their moves, but my thinking was all mixed up. The first big key to solving these two puzzles is to do the steps in the correct order; it definitely didn't help that the first tutorial I watched was a "Part 3 of 4" that didn't review the fact that you need the edges solved before attacking the centers. When I finally understood the order of battle, it was more than halfway won. The other mystery that I really needed clarity on, and which I hope this tutorial has provided, is the nature of that "w" move that's part of the petal-swap algorithm. Also, if you can keep straight which of the three algorithms in this solve turns the top-back corners of the cube (viewed face-on), vs. the other algorithms that turn the right and left corners (viewed edge-on), you'll go far. And finally, don't forget the "times 2" bit in the center swap algorithm, and which side to start on depeneding on whether you want a clockwise or counterclockwise cycle.
All that said, the Super Ivy and Rex cubes have turned out to be really fun puzzles. Besides the quirky geometry of them, the fact that they don't practically solve themselves (like the Ivy Cube) appeals to me. Also, it takes a bit of time to solve them; certainly worth the trouble of scrambling them, despite that pesky scrambling notation. And finally, despite the fact that the solution can be reduced to three algorithms, one of them repeated numerous times, there's also a certain strategic challenge to their solution as well. You have to make decisions about which centers, and which petals, to swap. You may have to do quite a bit of nudging petals around to get them where you want them. You have to do, and undo, strategic setup moves, sometimes multiple ones in the proper order; and sometimes you're forced to make short-term sacrifices to accomplish an immediate goal. And the way the petal-swapping part of the puzzle gets increasingly difficult, then rapidly grows easier at the very end, creates a sense of dramatic tension building up and relaxing, like a story. Plus, they're cute and the moves feel great in your hands. I can't think of any reason not to endorse these puzzles, fully and unreservedly – but by just a little bit, the Super Ivy Cube more so than the Rex Cube.
