Neil's Puzzle Building Blog
27May/140

Penta Beams

Oskar van Deventer has been at it again, and this is the latest (well latest published as far as I know) design from the incredible puzzle generating mind of the Dutchman. This time it's an intersection of six pentagonal sticks to form a pyramidal shape. The goal is to take the sticks apart, and put them back together again.

Penta Beams by Oskar

Penta Beams by Oskar

3D printed by Shapeways, the pieces are dyed into six bright colours (plus black and white) and have a solid feel to them. the trapped powder inside each stick really adds weight and a feeling of quality that can sometimes be lacking in Shapeways printed materials. The puzzle measures approximately 3.5" tall once assembled, with each stick being 3.5" long with a 7/8" cross-section.

The sticks just keep on holding.

The sticks just keep on holding.

The fit is perfect, and each of the sticks holds the others at the right angles all the way until the last two pieces. That certainly makes this a much more enjoyable puzzle to play with, as you don't feel like you're fighting your own fingers and wrestling with a dexterity challenge.

Six pentagonal pieces

Six pentagonal pieces

There's one key piece, followed by five notched sticks which must be removed in sequence to take the puzzle apart. While it's not trivial after the pieces are mixed up, I'd say that this is certainly an approachable puzzle for most people. Having taken it apart, and mixed the pieces, then left them alone for a while, I was able to put it back together in around 20 minutes. Now, I'm no expert in this style of assembly puzzle, but it was both fun and a good level of challenge for me.

Penta Beams is available from Oskar's Shapeways shop if you'd like a copy of your own.



22May/140

Cast O’Gear

It's been a while since I reviewed any of the Hanayama puzzles, and I have quite a few to get through, including a few of the newer puzzles. The Cast O'Gear though is one from my early puzzling that I remember solving having been given a copy by my Dad. Designed by Oskar van Deventer, and originally named Sunflower, this was entered into the IPP Design competition back in 2001 where it received an honorable mention. In 2002, Hanayama produced this version under the name Cast O'Gear.

Cast O'Gear in the starting position

Cast O'Gear in the starting position

The antiqued Bronze look of the puzzle seems to have people divided about its appearance. I personally like it. It's a fairly average size for a Hanayama puzzle, measuring in at 3" at its widest, by 3.5" tall and 1.5" deep it's a solid puzzle although not too heavy for its size. The goal is to separate the two pieces by following the step maze to the exit.

In its starting position above, there are a number of key features that help with solving the puzzle. The small triangle on one face gives both direction and orientation information about the cube. and the indents on the 'gear' allow for orientation of the gear relative to the faces of the cube. One additional piece of information not visible in the photograph, is the arm which is inside the cube has a hole in it, giving the ability to create a visual reference for each arm.

The exit to the puzzle is on the opposite face of the cube, and the cutaway on one of the arms can pass through a corresponding groove in the face of the cube, when it has been aligned correctly. There are 120 possible states that the puzzle can be in based on which arm is inside the cube, the orientation of the gear, and which of the six faces the gear arm is inside. To make things a little harder, it's not possible to transition from all faces to all other faces. The cube is designed with a number of beveled edges to allow the gear to rotate, as well as a couple of sharp edges which prevent the gear from rotating. So often you think you're on the way to the exit, and find the path blocked by a sharp corner.

Each face also has a curved cutout in the central cross, which allows the gear piece to be rotated by 90 degrees. You can only move in one particular orientation though, governed by where the cutout is, so again you find that you may want to rotate the gear in one direction, however find that path blocked.

Moving the gear around the cube

Moving the gear around the cube

With some logical thinking and planning, this shouldn't be too tough a puzzle, however it's easy enough to get lost and go round in circles, trying, and re-trying the same paths, and making little progress. It had been a long number of years since I had solved this puzzle last, and it was certainly no walk in the park. I spent a good half hour just fiddling before realising why certain moves were blocked (must have been having a slow day) and then setting about to find the correct path to the exit. By checking the orientation that the gear needed to be in to allow it to be removed from the cube, then working back through the possible rotations and moves between faces, the path was easy enough to navigate, despite needing some paper and pencil to plot the moves in reverse then execute them.

Solved, with the gear removed.

Solved, with the gear removed.

There are a minimum of 16 moves needed from the starting position to separate the two pieces (if my counting is correct), however as with any maze, you may end up taking far more moves by the time you take into account the dead ends and back tracking that is likely to end up in the solution path.

There are lots of puzzle shops where you can buy your own copy, and it's available on Puzzle Master as you might expect. If you don't have a copy, I highly recommend it, as it's a great fiddle toy, that you can spend a lot of time just moving the gear around the cube, and not really trying to solve the puzzle.



2Nov/114

Buffalo Nickel

The Buffalo Nickel is based on a puzzle design by Oskar van Deventer and was made by George Miller for IPP 20 in Los Angeles is a large burr style puzzle where the object is to fit the two burr pieces into the main body of the coin to complete the border of the coin. It takes 9.5 moves to put the three pieces together into the solved state. I'm not quite sure where the half move comes from, but I'll take George's word for it (more on that later).

The front of the Buffalo Nickel

The front of the Buffalo Nickel

The back of the Buffalo Nickel

The back of the Buffalo Nickel

This puzzle was brought to me by a friend after they visited my house recently and I showed them a few of the puzzles in my puzzle cabinets. Her daughter who was with her mentioned that they had this big coin puzzle where you had to put the two pieces into the coin and it was really hard. She had spotted it in a garage sale, and bought it as she thought it looked pretty neat. Unfortunately, she hadn't been able to solve it, and nor had her mum so it was sitting in its three pieces. Before I could say much my fiancée announces that I'll solve it for them if they bring it to me. Well, not much I can really say at this point other than, "Sure, I'll give it a go". After all how can you disappoint an 11-year-old when she's been drooling over the puzzles in the cabinets.

The puzzle promptly appears over the weekend and an excited 11-year-old hands me the puzzle and says there you go.

The three pieces of the Buffalo Nickel

The three pieces of the Buffalo Nickel

As you can see the two pieces are simple burr pieces which both interact with each other inside the puzzle and with ledges and holes inside the body of the coin. It's a big puzzle, measuring around 4" diameter, and being metal has a good weight to it.

I should point out that when I was handed this puzzle, I was at my Son's football game (American Football, not Soccer for all those back home in the UK), where I was in charge of the grill. I had just sat down to eat some lunch, so had a burger in my hand when I was given the puzzle. With an excited 11-year-old in front of me I thanked her, and said I'd try once I finished eating.

So finishing my burger, I take a look inside the body to see how much I can see, and look at how the two pieces interact. It seemed fairly straight forward, so I insert both pieces, and play around with how they interact inside the puzzle. I'm able to get the right hand piece in place fairly quickly, but it's blocking the left hand piece from falling into the correct spot. Taking the pieces out, I play around with just the left hand piece to see how it fits, and it becomes pretty clear that it has to be very carefully aligned to drop into place. The tab on the left has to fit very precisely into the body, and any small angle in the piece prevents it from being inserted.

With that knowledge, I put both pieces back into the puzzle, and have it solved a minute or so after that. All in all it took less than five minutes for me to solve.

Getting up from my seat, I take the solved puzzle to my friend and I'm greeted with "What, What, how, you ....". I just laughed and said that it was a very nice puzzle, did she mind if I took a few photos to allow me to put up a review of it.

Given that this was an IPP puzzle, the card which accompanied the puzzle for IPP 20, has the following information about the puzzle. The copy that my friend has doesn't have the card with the puzzle, or its original box.

"The Buffalo Nickel Puzzle is based on the Nine-and-a-half-Moves puzzle by M. Oskar van Deventer. It is composed of just three pieces that fit together in such a way to hide a secret compartment. Although the three pieces are flat and lie in a single plane, it takes a remarkable 9 1/2 moves to solve."

There is a very interesting article from Oskar about the puzzle, that does contain the solution (you've been warned) which you can read here if you're interested. I know I mentioned at the top that I didn't know where the half move came from, however in Oskar's article, he describes the slide and rotate which is required in the solution as a move and a half. So that explains where the half came from!

I'm very happy to have been given this puzzle to try, and it was a fun little puzzle to play with. Thanks to my friend to lending it to me. Now she has to go solve it herself as she knows it's possible now!