## The Professor's Cube

### V. Solve the Middle Outer Edges

This has the same steps as the "Top Edges" section; move an edge from the bottom, knock it down or invert it.

Hint: Try to finish as many outer-edge pieces as you can, by merely rotating the mid-upper and/or mid-lower horizontal layers first. You should be able to wrap up a couple of outer-edges quite easily that way. There is no guarantee, but the odds are in your favor.

Chances are, you have outer-edges on the bottom layer that need to be moved up to the equator. Rotate the bottom layer to set the edge piece in the starting position. Before doing any moves, you must make sure that the patterns are just like the diagrams below. The colors may be different, but the pattern must be the same. Notice how the edge piece (on the bottom, in the starting position) looks like it's mismatched with the front side.

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## B2 M- B+ L-B- M+ B+ L+

A middle outer-edge piece could already be in the equator, but in the wrong spot. Use the sequence below to knock it down to the bottom layer. You can move it back up to its proper place later, by using one the sequences above.

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## M- B- R-B+ M+ B- R+

In case you haven't noticed, these sequences look very similar to the "move-up" sequences. In reality, all you are doing is moving up an edge from the bottom, which in turn knocks down the target edge from the equator.

Hint: Use the "Knock-Down" sequence only as a LAST RESORT. Almost all the time, that edge can be knocked down to the bottom layer later anyway, when you are merely doing a "Move-Up" sequence with another middle-edge piece.

And finally, to invert a pair of outer-edge pieces, already at the equator:

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## M- B- R- B+M+ B- R+ B- O- B- R- B+O+ B- R+ B- M- B- R- B+M+ B- R-

At 23 moves, this is one of the longest sequences used in the Professor's Cube solution. If you do not want to memorize it, then knock down the pair of edges (one at a time), and then rebuild them (one at a time) later to their correct positions, using the "move-up" and "knock-down" steps.

It may be scary at first. When solving any of the middle edges, the top side gets scrambled temporaily; but after the moves are over with the top side remains intact, along with the other middle outer-edges you just carefully put in place. Even the scrambled middle inner-edges are still where they used to be! Speaking of scrambled eggs, let's forge onto the the...
Middle Inner-Edges.