26 August 2019

2019 Parts Fest #1: Duncan Lindbo's Castle Maze Puzzle

Posted by Admin
After his initial creation using the new LEGO® stud shooter, Duncan Lindbo returns with a wholly different idea, this time using the new gear wheel, as part of our ongoing Parts Festival.

When I got my shipment of Gear Wheel 4x4, Z10 (Design ID 35443) from New Elementary, it didn’t take me long to come up with an idea for a MOC that used them. With a diameter of six studs including the teeth, and four studs without, they’re big enough to have some space to work on without requiring a tremendous investment in parts. Also, the ones I got were Dark Stone Grey/ Dark Bluish Gray (Element ID 6252371), which works well for a variety of uses (they also come in Medium Azure, 6238331).

So I built a slide puzzle. Not just any slide puzzle, but one in which the pieces also rotate!

The goal is to connect the entrance and exit of the maze by sliding and turning the puzzle pieces. I’m a big fan of the Myst games, and this puzzle feels like something you’d come across on a desk in one of those games, where playing with the “desk toy” actually controlled a real maze you’d need to traverse. I think Jareth the Goblin King would approve as well...

Astute puzzle solvers and mechanical engineers will likely have already realized that, because of the fact that the gears are always intermeshed, you can’t actually slide the four pieces in the center of the puzzle. A more refined version of this idea might include some sort of mechanism that disengaged them in some way (maybe push the gears one plate higher?) when sliding a piece.

Perhaps the most interesting aspect of this build is the puzzle pieces themselves. The bases are pretty standard slide puzzle pieces, with tongues on two sides and grooves on the opposites, but because the gears need to be intermeshed, the grid size for each piece is 5x5 studs. This in turn means that to secure the gears to the puzzle pieces, we need a half-stud offset in each direction in order for the 4x4 turntable base to connect to it. Fortunately, 2x2 jumpers make that easy. I think using blue ones would have made the MOC look better; they’d have probably worked better with the “swampy/flooded castle” idea I had and provided a visual explanation as to why you wouldn’t just go through all the gaps between the maze sections, but alas, I don’t have nearly enough blue 2x2 jumpers to make that a reality.

The fact that these gears have an even number of teeth that’s not divisible by four means that you can mesh the gears in such a way that their studs will all be aligned when “at rest”. That means after every 90° turn of a puzzle piece, the maze pieces will all still be aligned. If you look closely at the puzzle without the maze pieces on top, you’ll see what I mean: half the gears have their little indicator arrow pointing “up”, and the other half are pointing the “right”.

On top of the gears sit the actual maze pieces. I really wanted the pieces to have defined walls, which ended up limiting the maximum size of them to 3x3 if I wanted the gears to still be able to turn. Instead of jumper plates, I instead used 1x1 round plates on the bottom of each maze piece, and stuck them on the tops of each gear in between the studs.

Despite some of its shortcomings, I’m generally pleased with how this came out. Now if you’ll excuse me, I’m off to BrickLink for some blue 2x2 jumper plates...

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Products mentioned in this post were kindly supplied by the LEGO Group. All content represents the opinions of New Elementary authors and not the LEGO Group. All text and images are © New Elementary unless otherwise attributed.


  1. Woah! As someone who loves escape rooms and all kinds of puzzles in general, this was a delight to see such a creative use for the new gears. And very interesting to read about the challenges you had when designing it, builds like this are always more complex than you think so to see its inner workings makes it even more impressive! I'm definitely going to see if I can build my own & incorporate it into my home-made escape room!

  2. Wow, someone give this man a handshake and a trophy! This build is both a great idea for a model and a great idea for new parts. The execution is stunning as well. Great work Duncan!

  3. PLease cooperate with some toy company so they can mass produce this one..