Logical Progression My A£$€!

Oh! Now Look At That.......Hmmm!

Errrm! I might have been a little stupid last week!
X-ray cube properly solved!

On Facebook, it had been asked by someone what our approach to solving puzzles was. There were several fantastic answers by puzzlers who are far better than me at actually solving these blasted toys and I had to admit that my approach was a little scatter-brained:

I think this is a good approach!

Before I start on today's puzzle review let me have a small catharsis and expose the poor state of my brain to you all! In my recent review of all the upcoming Pelikan puzzles, I had given the impression that I had solved and enjoyed Volker Latussek's X-ray cube - Enjoyed? Yes, solved? Blush...nope! Unfortunately, I have to own up to being really not terribly bright!! I had slid open the lid, poured out the contents without paying attention to the arrangement and then assumed that the challenge was to put all the odd shapes back inside and close the lid again. I thought that the name of the puzzle came from the X shape that was visible through the hole in the top and bottom of the box. Doh! Now, whilst I had found doing that a significant challenge (and it is certainly one that you all should try), this was definitely NOT the main aim of the puzzle. Both Volker and Jakub contacted me to inform me that I was not terribly bright! (my words, not theirs).

I have spent another hour or so performing my usual (as shown above) approach to solving puzzles spread over the last couple of days, I was entirely unsuccessful (as usual) and had to try Allard's silly "Thinking©" thing! I was about to admit defeat when a thought did actually spring to mind (obviously it was not one of my own thoughts and I would really like to know who put that thought in my head because it was a good one) - I tried a few new things and it seemed right. I tried a few more and, suddenly, I had solved it correctly - the reason for the name, X-ray cube (as you can see at the top of the post) is that when the puzzle is solved properly, you can see straight through it! Yay! Now I have to work out how to put it back to the unsolved position....again! This is really quite a fun challenge which is proper tough if you just try random moves and a lovely mental exercise if you want to use Allard's silly approach.

Now on to my regular reviewing! Which unfortunately reveals yet again that Allard's fascination with using the brain might actually be right! Damn! I hate saying that!

Logical Progression

Logical progression is a design by Rick Eason and was made by Eric Fuller. You may not know it but Rick is responsible for the design of two of the best disentanglement puzzles I've ever worked on - Tricky dick (aka Day Trip) - available here in Australia and here in Europe) and it's tough brother Return of Tricky Dick (aka City Trip) - also available from Tomas Linden here (at the moment they are not available from PuzzleMaster for those of you in the Americas). It had taken me a very long time to solve those two brilliant puzzles and, true to form, it required thought rather than random movements to solve them.

Initially, the Logical Progression was not particularly interesting for me because it wasn't as beautiful as most of Eric's usual creations and I didn't realise who the designer was when I first looked on the store. I thus missed out on the first batch after they sold out pretty quickly. Only later, enticed by the designer's name, did I spend some time reading the blurb on the product page. I had been much too dismissive on looks alone. I realised that this would almost certainly be a really fun challenge! Lesson no. 1 - always read the description as well as drool over the pretty pictures. Eric's description said this:

"Logical Progression is a very unique cube. With only one solution which must be accomplished with serial assembly, it seems at first look that this puzzle will be a trial and error nightmare. However, the puzzle is designed such that scrutiny of the pieces will reveal their positional constraints; therefore the puzzle can be solved by analysis rather than guesswork."

Having finally gotten around to reading this, I decided that I should get a copy and contacted Eric, I was pleased to hear that another batch was due to be released - phew! When it was released, I missed out on the fancy exotic wood but still managed to get a copy in Maple and Oak. When it arrived it was a rather odd-looking and very rickety 3-inch cube. It definitely is not one of my most beautiful acquisitions! I really hoped that it would be as good a challenge as claimed.

Having taken the photo above, I pulled at it a bit and a cluster of pieces slid off and then another few. After removal, some of them swivelled around on the dowels and lost their orientation. Boom! There was no way for me to recall how the bloody thing came apart. I lay out all the pieces for my customary photo:

Oh dear! This looks rather more complex than I had initially thought!

Then I bunched all the pieces together so I could sit down and try to remake my cube. At this point I was beginning to regret my purchase!

OMG! I might be in trouble!

I received this puzzle in September 2019 and have carried a bag of bits around with me ever since then and have attempted to assemble the cube many many times. Bearing in mind my usual random movements approach, there was absolutely no doubt that I was doomed to failure! I idly tried a little thinking© and apart from gaining a mighty headache, I failed yet again. I probably spent 10 hours or so on it before getting fed up with having a rather unwieldy and painfully spiky lump in my bag. I read up the instructions again and headed to Rick's site for some encouragement and maybe even a hint or two. Rick claims that this is the very best of his puzzle designs and remembering those disentanglement puzzles, I was all the more determined to solve it myself. He does have a step by step assembly on his site as well as a text file going over the logical steps. I downloaded the text file and stored it without looking (honest guv!). I HAD to find the logical progression that Rick wrote about.

Having finally abandoned my usual random movement approach, I had to look at the puzzle and think about possible arrangements of the pieces. It consists of 16 different L shaped tetrominoes, each with holes in 3 of the voxels and a 4 voxel length dowel fixed inside one cube and which will run through  holes in other adjacent pieces. With only one 4 unit long dowel per tetromino and 16 in total, it is important to establish possible orientations for the entire puzzle. This was my first Aha! moment! It is definitely NOT as random as I thought. In fact, not only can you work out possible patterns for the rods, you can then narrow it down layer by layer.

Then I had to look at all the pieces and sort them into subtypes and decide on potential rows/columns - it began to look rather confusing on paper but many little Aha! moments were happening:

It looks much worse than it is.
As Rick says...it is a Logical Progression

The paper section was pretty much done with and it was time to play with my wood. Having established that certain rows had to have the dowels in certain directions, I worked on some random assembling of more limited pieces. This is much better than picking from all of them and just trying to lump them together! In fact, it became very obvious that 3 pieces needed to be placed first and there was only 2 possible arrangements for them. This could very rapidly be reduced to just one possible arrangement. Wow!!! I was using logic! Once I got started on the assembly by thought©, things progressed fairly quickly until I reached 2 completed layers and a few parts of a 3rd one placed.

Now what? Again, I only needed to look at the shapes that I had and think© about possibilities to very rapidly reduce the possibilities to just 2 for the next few pieces. More logic gave me the placements for the top 2 layers and then it was a fairly simple matter of disassembling a section just enough to allow various new pieces into place. After about 3-4 hours of logic, my cube was fully assembled again.

OMG!!! That was an absolutely incredible puzzle! It goes to show that beauty alone is not all that one should judge them on. The more puzzling I do over so many years now, the more I appreciate when a puzzle designer makes something that is pure cerebral solving for a mechanical puzzle. Thank you, Eric and Rick, for making me Think©! Bloody Allard and his fancy approach! Rassafrassarickarackets!!!