This family of 3" cube puzzles are each made of 6 similar looking pieces which slide in and out of each other along unexpected diagonal directions of motion. The classic "Barcode Burr" design follows a binary sequence of piece movement whereby it takes 64 moves to release the first piece, then another 32 moves for the second piece, followed by 16, 8, and 4 moves to fully disassemble!
Each of the six pieces is made from an identical "piece body" component and two attachments pieces called the "tab insert" and "pusher arm insert", so that's 18 total pieces to print (6 bodies and 12 inserts). The puzzle looks cool if you print the inserts from a different color than the piece bodies. These parts are all very easy to print because no support is needed!
In addition to the classic Barcode Burr insert set, included with this download are also insert sets for other puzzle designs of increasing complexity, all of which use the same basic piece body components.
For each puzzle, you will need to make:
(6x) piece body
(6x) pusher arm inserts
(6x) tab inserts
The piece body components are all the same regardless of which insert set you want to use, however if you plan to use metric hardware then make sure to print metric piece bodies in order to have adequate clearance for the screw heads.
The insert files are all organized with folder names that describe what style hardware is used (imperial or metric) and how much surface offset has been applied to the geometry in order to provide proper clearance between the assembled parts. Currently I am producing these puzzles on my Prusa i3 MK3 machines with 75 micron surface offsets and having great results so try the minus-75 files first; if you cannot get your puzzle pieces to fit together easily then use the minus-100 files instead. I realize that not all options are currently available for all insert sets so if you have and special requests please contact me or leave a comment.
The difference between the metric / imperial versions of the STL files mostly has to do with the diameter of the pilot holes for the screws. If you want to use M3 hardware instead of M2 then I recommend scaling up the metric files by 50% however I have not tried this yet to verify how well it works.
Depending on whether you've printed imperial or metric versions of the STL files, use either 2-56 x 3/8" or M2 x 10mm socket head cap screws to hold the pieces together; here are examples of screws that will work:
The Barcode Burr uses short socket head cap screws in lieu of pins projecting into the mazes, so use either 2-56 x 3/16" or M2 x 5mm depending on whether you've gone the imperial or metric route; here are examples of screws that will work:
If you have no personal preference in this regard, I recommend going the imperial route because the screw heads stand up taller and so there's better engagement with the maze sidewalls.
Aside from the Barcode Burr, every other set of insert pieces uses press-fit dowel pins instead of screw head projecting into the mazes. All of the 3x3 puzzles use 3/32" diameter x 1/4" long pins, however the QuadCode Burr (which has a 4x4 maze grid) uses 1/16" diameter x 1/4" long pins; here are examples of pins that will work:
In order to help align the pins during assembly, print out the included "pin pressing plate" which has a loose fitting hole allowing you to easily insert each pin by hand. Once the pin is seating into the pressing plate, flip the insert piece upside down and lower it down onto the exposed tip of the pin projecting out of the pressing plate; once you have properly seated the pin into the hole of insert piece then use your body weight in order to press the pin as deep as possible into the pilot hole of the insert piece. Due to the extreme amount of pressure generated on the downward facing tip of the pin during this process, it is important to support underneath the pin pressing plate with some kind of hard material like metal so that the pin doesn't blow through the back of the plate and damage your dining room table! Wow aren't you glad I told you about this, or otherwise you would be in a whole heap of trouble right now... you should buy me a beer.
OK seriously though, once you've seated the pin as far down as the pressing plate will allow it to go, then remove the pressing plate and seat the pin the rest of the way down into the pilot hole until it bottoms out. Once again it's important to press against something hard when doing this; wood probably isn't hard enough. Verify that the pin has gone deep enough into the pilot hole by test fitting it into one of the maze insert pieces; there should be a small amount of axial clearance between the tip of the pin and the floor of the maze path.
Once you've installed all of the pins into the insert pieces, it's time to assemble them onto the piece body components. The STL files for each insert piece are named according to which puzzle piece (P1-P6) they go with, but once you've printed them all out the filenames become irrelevant so use the rainbow colored roadmap info card (included in the "info cards" folder for each set of insert pieces) to help ensure that you're matching up the proper pusher arm and tab inserts together. Also, be sure to read the "assembly guide" and "help guide" info cards which explain how to use the rainbow colored roadmaps and "graycode" solution guides.
Refer to the rainbow colored roadmap in the info cards folder for each set of insert pieces for proper orientation of the pieces relative to each other:
piece #1 = red
piece #2 = orange
piece #3 = yellow
piece #4 = green
piece #5 = blue
piece #6 = purple
For the classic Barcode Burr, each piece can have three possible states: in, out, and removed. Other insert sets beyond the BCB have additional "middle" states possible, thus making them more complicated than the BCB to analyze from a purely logical point of view. One of the beautiful things about the classic BCB is that the pieces move according to just a couple of simple logical rules which are easy to understand:
piece #1 = can always move in/out
piece #2 = can move if piece #1 is out
piece #3 = can move if piece #2 is out and piece #1 is in
piece #4 = can move if piece #3 is out and pieces #1 and #2 are in
piece #5 = can move if piece #4 is out and pieces #1, #2, and #3 are in
piece #6 = can move if piece #5 is out and pieces #1, #2, #3, and #4 are in
An easier way to think about this is with one simple rule:
RULE #1: a piece can move in/out if the piece before it is out and every piece before that is in.
The other rule is about how you can add/remove a piece:
RULE #2: a piece can be added/removed from the assembly if every piece before it is in and every piece after it is removed.
These rules force the pieces to move in a binary pattern which looks like this:
piece #1: moves every 2nd time
piece #2: moves every 4th time
piece #3: moves every 8th time
so, that's a sequence of 32 steps in order to move the 6th piece out, and then repeat all of those steps over again to remove the 6th piece. Repeat the first half of that to move the 5th piece out and then do it again to remove it. Repeat the first quarter of that to move the 4th piece out and then do it again to remove it. etc... What you end up with is:
piece #6: removed from puzzle after 64 moves
piece #5: removed from puzzle after 32 moves
piece #4: removed from puzzle after 16 moves
piece #3: removed from puzzle after 8 moves
piece #2: removed from puzzle after 4 moves
total moves following binary sequence: 124
NOTE: there are a couple of alternate solutions for this puzzle possible whereby the top half of the puzzle is rotated 120 degrees relative to the bottom half; these alternate solutions do not properly follow the binary pattern. Also, there are shortcuts possible because opposite pieces cannot affect each others motion: pieces 1/5, 2/4, and 3/6 are opposites from each other.
So for example piece #6 can actually be removed in just 33 moves instead of 64 if all shortcuts are taken advantage of:
Please note that all of this discussion is only relevant for the classic Barcode Burr insert set; the other puzzles (TernCode, QuadCode, SuperCode, etc...) follow different rules which I will leave it up to you to discover on your own!
Good Luck, and Happy Puzzling!
11/14/2018: Uploaded all new versions of the STL files with more consistent naming conventions, and organized in ZIP archives. Uploaded minus-100 versions of the STL files for the BCB. Uploaded rasterized images of printed literature (puzzle info card, rainbow roadmap, graycode solution, assembly guide, help guide, artist info card). Uploaded STL files for all puzzles in the "Master Set" including TernCode, QuadCode, SuperCode, ExtremeTortureCode, and CoordiCode Burrs!
9/20/2018: Uploaded metric versions of the STL files in order to allow the use of M2 hardware instead of 2-56. Updated List of Printed Parts and Assembly Instructions accordingly.
9/18/2018: Uploaded new STL files with improved piece geometry in order to reduce overhang on the tab insert pieces so that support is no longer needed. Updated printing instructions to remove reference to support setup.
9/16/2018: Uploaded solution guide
9/1/2018: Uploaded new STL files with improved piece geometry, modified assembly instructions, updated recommended screw lengths and added new links to example hardware