October 25, 2009

From Matchsticks to Magic (Part 2)

In my last entry, I started writing about my experience at a mechanical puzzle talk given by Saul Bobroff and Chris Morgan that was organized by Eureka Puzzles.

After Saul finished his presentation, he handed it off to Chris.  Chris passed around sheets of paper that had number printed on them, and the objective of the puzzle was to fold the paper so that the numbers were in order from 1-8 from top to bottom. I was surprised that it actually ended up being pretty tricky: I figured out one of them but didn't get a copy of the second one.

Chris also did a demonstration of a puzzle/magic trick that involved a piece of paper with a door cut out of it. One side of the paper was decorated like a garden, and the other side was blank. He asked a volunteer to come up to help with this trick. He had her grasp the door on the paper and told everybody to close their eyes.

A few moments later, when we were asked to open our eyes, he had manipulated the paper so that it seemed as though the volunteer's hand passed through the door and ended up on the other side with the garden. This at first appears impossible, but if you think about it for a bit you can probably figure out how it was done. Finally, he concluded with the magic trick that he was practicing before the presentation started.

After the presen-tations were over, folks roamed around and played with all the puzzles that Chris and Saul brought. I first tried Spanner by Kirill Gribnev, which was made out of a full-size wrench, a chain, and a metal ring. Not too tricky, but a fun little puzzle that was nicely made.

There was also a large version of a nail puzzle around that I gave a try. I have no idea what it is called, so unfortunately I can't find a picture. It was quite large with maybe foot long nails that were a quarter of an inch thick. Definitely a good choice for this type of event, because it is almost indestructible.

Saul had some of his impossible objects as well, including Nine Drilled Holes, which I hadn't seen in person before. It is actually quite small, maybe a bit more than an inch square. It is very nice looking, as you can see from the picture. The idea is that there are nine holes drilled in the acrylic block, all but one of which are curved. The question is, how does one drill curved holes? They were actually drilled, according to Saul. Quite puzzling!

I also got to see 4 Street Elbows in person: it consists of four elbow joints that are connected in a circle. How could it be possible to add the last joint? I have a theory about this one, but with impossible objects you haven't really solved it until you have duplicated the feat. Saul said that the pipes are held in place only by the threads.

There were a bunch of other puzzles, but the one that stumped me was Mmmm puzzle by Hirokazu Iwasawa (Iwahiro), the same designer who made ODD Packing Puzzle, a very cool and award winning packing puzzle. Mmmm is quite simple: it consists of a box with a lid and four identical M-shaped pieces. The objective is to place all of the pieces in the box and shut the lid.

I had no luck with this, even though I worked on it for a good 10 or 15 minutes. In fact, I couldn't even get three of them in, which Iwahiro suggests as the first problem to attempt. I would guess that once you get three in, it is not trivial to figure out how the fourth fits, since he describes these as two separate problems.

I really wish I could have spent more time with this one, because I'll bet the solution is interesting. Unfortunately, these are sold out on the two websites that Iwahiro suggests, hopefully more will be made at some point.

After people were done hanging out after the presentation, everybody headed over to Eureka to see what was for sale. We ended up playing around with some copies of Perry McDaniel's Petite Fours, which were very cool. I solved three of them, but couldn't figure out Cinnamon Walnut Twist Cake. I am on the waitlist for the batch Perry is producing in December, so I guess I'll have to wait until then.

It was great meeting Saul Bobroff and Chris Morgan, and I also met Tim Udall and a few other collectors in the area. A very fun evening, I was glad that I was able to make it. Hopefully this will be the first of many puzzle gatherings I will attend.

Tomorrow, I'll write about a very nice puzzle box that I purchased from Eric Fuller.


  1. Brian, what is your e-mail? I would like to ask you something.

  2. Hi Anonymous: my email address is my full name (no punctuation) at comcast.net. I look forward to hearing from you.

  3. The 4 street elbows looks interesting. Is the object of the puzzle to disassemble the elbows and get them back together? Or does it all come apart and back together easily and the challenge is to just ponder on how you might re-invent the object?

  4. Hi Steve,

    Actually, 4 Street Elbows, like most impossible objects, is a one-way feat. The object is to figure out how it could have been done. I actually tried to recreate this puzzle over the weekend, but didn't have much luck. I think I have the right idea, but I didn't execute it correctly. I will ask Saul the next time I see him to see if I am on the right track. It is a pretty cool looking puzzle!

  5. This one interests me a lot...
    One more question then.
    Are these normal street elbows you can buy anywhere?
    Or were the street elbows made by Saul, and the puzzle is to figure out what is special about his street elbows that allows this 'impossible' 4 way connection?

    I hope it's the former.

    Btw - glad you are healing from your surgery. The first appendectomy is pretty routine, but I have yet to hear of someone surviving a second appendectomy.

  6. Hi Steve,

    I haven't asked Saul directly, but I was able to find some at Home Depot that looked quite similar. They are called 1/4" street elbows. If you want to buy one, they are available at http://www.eurekapuzzles.com for $75 or you can try to purchase directly from Saul which might be cheaper.

    I definitely like the idea of this one too. At first it looks un-spectacular, but when you think about it, it is impossible.

    I'm feeling better, thanks! Hopefully I can avoid that second appendectomy!

  7. Hey Brian!

    I know this was quite a while ago now, but if you're still after the Mmmm packing box you can get it from Sloyd here for a pretty good price:



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