MF8 Takes it to the Max...or is it Plus?

Skewby Copter Plus

At the back an edge turn, diagonally a corner turn

Here I am again, fresh from a day of DIY yesterday replacing light switches, sockets and fused connection switches and actually managed to NOT electrocute myself for once! I usually do a batch at a time and test them as I replace them. Sometimes I forget to switch off the mains before moving on to the next and, bloody hell, it hurts when the shock spreads across your chest! Here in the UK, we use 240V which really is quite powerful and, as we say in Yorkshire, it "smarts" a bit! I have set a record of completing a whole day without any pain (apart from the quadricep agony of doing 300-400 squats) - who knows, with this kind of luck, I might even manage to solve a puzzle soon!

Just a month ago, I discussed how I was going to extend my advice to progressing twisty puzzlers to include a special group of new puzzles that consist of two different twisty puzzles combined into one. So far in this group, the amazing Chinese producers have made the Grilles II cube and the 4 Leaf Clover Plus cube. Now the ultimate in this group (at least so far) is the Skewby Copter Plus cube has been released and after an initial period when it was in very short supply, it is now generally available. This puzzle, as the name suggests, is a mixture of the Skewb, a simple deep cut corner turning cube and the favourite of mine, the Curvy Copter. Not just the plain old Curvy copter but the Curvy Copter PLUS which allows a whole lot more movements than the original. The Curvy Copter plus was mentioned in my article on the extreme forms of edge-turning puzzles but has never been properly reviewed by me because of some major flaws in its' design.

Curvy Copter Plus cuts across the centres

Allows swapping centres and corners

The extra cuts in the plus version allow the centres and corners to be swapped which really adds to the fun but the design leaves the protruding pieces sticking so far out that they interfere with further turns and it quickly becomes completely locked up after inadvertently pushing past blockages.

This new Skewby Copter plus can be used as a Curvy Copter plus with the advantage that the puzzle has been fully redesigned such that the overhang bandaging has been completely eliminated. This is the puzzle that should have been released in the first instance - as just a Curvy puzzle it is FANTASTIC! What-is-more the additional Skewb cuts are possible even after all the Curvy Copter moves have been made and, on top of that, it is possible to perform half Skewb turns and then STILL make edge turns! This can lead to an amazing scrambled mess which looks impossible to solve. To show how amazing this puzzle is, I created a video showing how it moves and how to perform a full scramble - it takes a good 15 minutes to scramble it but you don't have to watch the whole thing to get an idea of how it moves.

Having learned how it moves and worked out the approach to get the best scramble - yes, it is always fun to have a twisty puzzle that is so complex that you need to plan the way to scramble it, you end up with an almighty mess that looks almost impossible to solve:

Dear Lord, what have I done?

Despite this horrific appearance, if you are brave enough to buy this puzzle, you really MUST perform a full scramble! It is actually very solvable! In fact, I would go as far as to say that this puzzle requires no more knowledge or fancy algorithms than are required to solve the base puzzles that it is based upon. Yes, if you can solve a Skewb and a Curvy Copter then, with a bit (maybe a LOT) of thought, you can solve this monster.

The first challenge is to get it back to a vague cube shape which means reconstituting the edges into the correct diamond shape like the one above. Then put the corners back into corner places and centres back into centre positions. Just thought alone and logical movements are required. At this point, some of the centres will appear to be sitting not quite flush with the cube surface and they will need to be temporarily taken out of position to a corner and rotated around the cube before placing them back into position and this time sitting flush. Finally, you will have a cube shape - this took me a few hours the first time but now I can do it in about 15 minutes.

Zachary and I worked for ages to get this far

I took advice from my Burmese boy and we had a fun time pairing up the triangular centres with the rectangular centres and the outer rectangular centres (each needed a different technique but no fancy algorithms) to produce complete petal-shaped pieces. At this point, it looks like I was well on the way to solving it but...take note of the diamond-shaped edges...they consist of 4 pieces and none of them matches up. Despite discussing it for a few hours Zachary could not come up with a way to fix the edges so it was back to the drawing board. Ignore the centres/petals, and make the edges first.

Recreating the edges was a huge challenge! Again, there are no fancy algorithms, just a combination of skewb setup moves then Skewb pairing of pieces and Curvy Copter moves to store the pieces - this left me with all of the small dual cloured pieces paired up and in the correct position. FABULOUS! Next to place the single colour diamonds within the edges. I was stuck for a while. A long while! Then I remembered what happens to the centres when making corner moves on a Skewb. A fantastic Aha! moment occurred and I was suddenly able to move them about at will. The hardest part was remembering my setup moves. It took me a couple of days but Zachary and I finally recreated all the edges:

That is one talented cat!

As you can see, the forming of the edges did break up the outer centre pieces from the inner two parts but putting them back together is almost trivial for anyone who understands the jumbling moves and orbits of a Curvy Copter. Another day and my puzzle had been reduced to a simple Curvy Copter solve and away I went...except this happened:

All solved except 2 corners out of place

In the normal Curvy Copter this is impossible - In fact, the "law of the cube" states that it is impossible to have a requirement to swap or move just 2 pieces - there MUST be a third piece that needs to turn or swap position. I will not give it away here but if you think about it, it is quite obvious where the third swappable piece might be and luckily that fix is quite simple without disrupting everything that has been done before. Zachary was very smug when we finally managed this:

Simply brilliant! Both cat and puzzle!

Of course, one has to solve a puzzle several times to prove that it was not simply luck as well as to ensure that other nuances have been found and understood. I scrambled it at least a half dozen times and convinced most of the nursing staff at work that I am crazy when I showed them how it moved and how mixed up it got. On my third attempt, I was rather shocked to find this at the very end:

Just one turned corner

The solution to this is definitely NOT straightforward - it requires a massive disruption of the puzzle and then resolving it with the corner placed correctly. I have subsequently worked out that this can be checked for earlier on during the solve (just after the edges have been created) and fixed before doing much more that needs to be undone.

In conclusion, both Zachary and I think that this particular twisty puzzle is one of the very best puzzles ever to have been created! I would go as far as to say that everyone should own one. It is the Curvy Copter plus that should have been released from the beginning (and if you wish can just be scrambled as one) as well as providing a massive challenge for any twisty puzzler when they introduce the Skewb turns. It is probably not suitable for beginners but I would hope that you would grow your skills into it with time. Just BUY it! It will be appearing in my top ten(ish) of 2019.

Phew - Now I need to solve something else quickly for next week!

Enjoy the rest of your weekend guys and gals.