I’ve wanted to make this Two-Look OLL tutorial for a while, and finally found the time. Although the video embedded below is comprehensive (read: long) and should stand alone, this post’s further background and table of algorithms should help with learning/practice.
What is OLL?
The third-step in 3×3 solving under the CFOP/Fridrich Method is OLL (Orient Last Layer). By the OLL stage, with the Cross and F2L complete, the bottom face and first two layers will be solved. The goal of OLL is to orient the up face stickers (generally yellow for white-on-bottom solvers so that all are facing up and none are facing “out.”
There are 57 possible cases/states at the OLL stage, too many for most cubers to learn/remember all solutions. (Two years in, and I know only about 30 of them….) Two-Look OLL is designed to lighten the burden by breaking OLL into two steps. The first step (or “look”) of Two-Look OLL is to orient the four edges, forming a yellow cross or plus-sign (ignoring the edges). The second “look” orients the four corners so that yellow faces up, completing the top face. The center cubie is, of course, fixed and can never be “un-oriented.” As the Speedsolving Wiki summarizes:
[Y]ou do not need to know all 57 OLLs to use 2-look OLL, rather the system is divided up. By first orienting the edges (3 cases), then orienting the corners (7 cases), orientation of all pieces on the last layer is completed.
I think we all can agree that 10 cases is better than 57!?! Here’s a video teaching and contextualizing them:
The Mouse OLLs (##3, 4) are hard. Not so much their execution (certainly the Sexy Move variants aren’t all that bad), but orientation. Where does that corner go? Top-right? Bottom left? And what about that side with just the un-oriented edge? Which is Mouse and which is Anti-?
Having concentrated on these OLLs quite a bit, I now no longer mind them. Here’s a simple table and video tutorial — its soundtrack a tribute to Lou Reed, RIP — followed after the jump by further explanation.
Generally, I find the OLL “dot” cases frustrating — there are a bunch of them, they’re hard to identify/distinguish quickly, and their algorithms are long. A few months ago, I worked on a couple OLL dot cases that I had previously two-looked. Those came rather easily. Then I got side-tracked by the Megaminx, 4×4 modding, and PLL time attacks.
I decided to work on more OLLs last week, after stumbling onto Ottozing’s very good Cubing World video showing all of the dot cases. Specifically, these three:
(r U R’ U) (R U2′) r2′
(U’ R U’ R’) U2 r
M U (R U R’ U’)
M’ (R’ F R F’)
(r U R’ U’) (L2 l2′) (U R U’ R’) U’ M’
‘Twas another beautiful Southern California weekend with many an hour of relaxing in and by the pool. With a nice Punch stogie, Grateful Dead (2/14/68) on the hi-fi, and some new “dot” OLLs in the mix. Another dot OLL video coming soon....
A friend and I have a unspoken tradition of buying gag gifts for each other off our Amazon wish-lists, which amounts to us placing a bunch of random stuff on the lists to see what the other orders. Traditionally, it’s been music or movies, but we’ve definitely had some weird things come up — digital home thermostats, drill bits, and the like. Long ago, I placed a stickerless Dayan Megaminx (a dodecahedron shaped puzzle) on my list and forgot about it. I had no real interest in it, had no expectation of ever being able to solve it (I was a 2-minute 3×3 solver at the time), and, more than anything, thought it would be a funny item for the wishlist. Lo and behold, it arrived at my house last December. I messed with a few times, got frustrated, and stashed it on my shelf.
A couple days ago, my 19-month-old brought it over to me, having scrambled it on his way. My OCD thusly challenged, solve it I had to. Which meant learning how to solve it.
I approached it entirely intuitively after realizing through a couple web searches that it’s essentially a complicated 3×3 — with 12 faces (rather than six), each with 5 edges and 5 corners (rather than 4). I experimented a couple times and then, on my third, decided to give it a go on video. Here is the result — a 10-minute solve (excluding the last layer), presented at 3x speed: Continue reading
So, yeah, I’m still cross training, although I don’t expect to harvest any significant improvement for a while. In the meanwhile, I decided to learn a couple more OLLs that seem to crop up frequently — the single dot cases. The two cases (OLLs ##1 and 2 on the speedsolving.com wiki) are mathematically somewhat rare — with their probabilities at 1/108 and 1/54 respectively. That’s the equivalent of a 1-in-36 (or about a 2.8%) chance of having either of these cases arise during a solve. They seem to occur more frequently for me, probably just because not knowing how to one-look them made them more conspicuous.
I don’t usually post about each OLL or PLL I learn. But there seemed to be a dearth of tutorials on these two cases, with the few videos I found online lacking any technique focus or finger-trick explanations. Also, both of these OLLs seemed vulnerable to simplifying alternations to make them more accessible to beginners or novices. Here’s my short video tutorial:
I haven’t spent much time at all on 2x2s. I actually think they’re fun puzzles, but just never really got that into them. I basically got a V-Cube 2×2 a month after getting into cubing, landed a 27-second on-video solve on my first try, got a 16-second solve a few days later, and then shelved it.
2×2 OLL GUIDE HERE: DOWNLOAD
When Crazybadcuber posted his excellent 2×2 tutorial (embedded below) the other day, I decided to order a better 2×2 (a WitTwo Type C v1) and try again. The last time I played with a 2×2, I treated it as a 3×3 with no edges. Which, of course, is right. But applying 3×3 algorithms is not very efficient. For example, I used to treat this 2×2 case like this 3×3 case . Of course, the 3×3 algorithm will work. But it takes 12 QTM moves with a couple D layer moves (which I find hard on a 2×2). By contrast,
the 2×2-specific an alternate 3×3 algorithm takes only 6 QTM moves — and is crazy easy: an F turn to setup, a Sexy Move, and a F’ to finish. EDIT: The key is that these three are equivalent: . Once you ignore edges, there are multiple 3×3 OLL cases to choose from for each 2×2 OLL case. Continue reading