Skewb

The Skewb is kind of like the Pyraminx. But different. I have never seen inside a Pyraminx, but I imagine it has a core with an arm for each of the 4 corners. When I first got my Skewb, it was defective and kept falling apart. So I got to see that it has a core with 4 arms. Two go to two opposite corners on one face of the Skewb, and two to the skew corners on the opposite face. The Pyraminx has 10 functional pieces: 4 corners and 6 edges. The Skewb has 14: 8 corners and 6 centers. The centers can be solved just like the Pyraminx edges without disrupting 3 solved corners. But doing so scrambles the extra corners. At least the way I do it. So I have a different strategy for solving the Skewb than I use with the Pyraminx.

The Basic Strategy for Solving the Skewb

  1. Get two opposite corners on one face.
  2. Get the two skew corners on the opposite face.
  3. Get the remaining 4 corners.
  4. 3-Cycle the centers into place.

Step 1: Get two opposite corners on one face

This takes at most two twists.

Step 2: Get the two skew corners on the opposite face

This takes at most two twists.

Step 3: Get the remaining 4 corners

The Move R swaps 2 with 8 and 4 with 6, and twists 4, 6, and 8 counterclockwise.

( The Move R ) x 2 twists 2 and 8 counter and 4 and 6 clock.

( R↑ L↑ R↓ D← ) ( R↑ L↓ R↓ D→ ) twists 1 clock and 5 counter.

In order to understand this mumbo jumbo we need to define some terms. When I first started analyzing the Skewb I had to come up with a way to talk about the corners. This puzzle doesn’t have nice neat layers like a normal cube. So I arbitrarily numbered the corners like this: ULF = 1; URF =2; DRF = 3; DLF = 4; DLB = 5; DRB = 6; URB = 7; ULB = 8. When I work with the Skewb I hold it so the center square’s sides are horizontal and vertical. The top is facing me. ULF = 1 is the corner at the bottom. URF = 2 is the corner at the right. To do R↑ means to twist the right half of the Skewb so that the corner at 2 goes to 6. Similarly L↑ means to twist the left half of the Skewb so that the corner at 8 goes to 6.

( The Move R ) means R↑ L↑ R↓ L↓

Step 4: 3-Cycle the Centers

To cycle the centers without scrambling the corners was tricky to figure out. This time let’s start with the definitions. Front is the center surrounded by the corners 1, 2, 3, and 4. Left is surrounded by 1, 4, 5, and 8. Back is surrounded by 5, 6, 7, and 8. Hold the Skewb with the top facing you, Front at the lower right, Left at the lower left, and Back at the upper left. R↑ moves Front up. L↑ moves Left up. U→ moves Back to the right. To move Right to Back to Left to Right do the following 3-Cycle:

( ( R↑ U→ R↓ D→ ) ( R↑ U← R↓ D← ) ) x 2

The first time it moves Right to Left to Back to Right, but it also swaps corner 1 with 7 and 3 with 5. Doing it the second time puts the corners back home. The same move done once on a 3×3×3 cube is a simple corner 3-Cycle. But on a Skewb Up-Replace-Down has a greater effect than it does on the cube.

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