Introduction: Win Pro Membership for a Year... Solve This Puzzle

Picture of Win Pro Membership for a Year... Solve This Puzzle

This is a 3D printed puzzle that has as much to do with illusion as it does with problem solving (I'll explain that after it's solved).  Two very simple pieces shaped exactly alike, need to be assembled to form a pyramid.

It's not that easy...

...And I'm not disclosing the solution.

What I'll do is give a year's pro membership to the first person who makes these, solves the puzzle and adds a photo of the finished pyramid in the comments below to prove it.

The stl file is for 6 sets.  The pieces are small, will fit into your pocket and allow you to take them with you to hand out.  If anyone wants a single piece, let me know and I'll publish the file for a single piece.  

Trust me, you'll want a lot of them.  They make great hand-outs.


Update - June 22, 2012:
New Pro Member Mathlas has won this contest using "old" technology.  He posted a photo that looked so much like it was computer generated, I had to make sure he really made it.  Sorry for the delay, Mathlas and congratulations.  

Update - July 18, 2012
It's been a month since the contest and time for me to explain the difficulty behind this puzzle... First, there's a mild optical illusion going on with the rectangular part of the shapes.  The square looks a tiny bit longer in one direction. your subconscious, like your boss, will tell you that rectangles only fit together in one direction, but won't tell you why.  

Next, and this is more diabolical: when asked to make a pyramid, everyone will think of an Egyptian pyramid.  Egyptian pyramids have 5 sides... 4 triangular and one square (the bottom),  This pyramid, is a true pyramid with only 4 sides,,, All of them triangular.  It's very difficult trying to solve a puzzle when your blueprint is of something else.

And thanks to everyone else who replied.  I'm going to be busy sending off badges for quite a while :)

And while you're voting for me, why not check out all of my other Instructables using my own Chindogu SMARTPHONE APP (It's free, kinda cool... But, clearly worthless.  Ya gotta check it out at  

Step 1: Anyone Can Win:

Picture of Anyone Can Win:

It's not fair that the only people who have a chance to win the pro membership are those with a 3D printer.

Here are the dimensions you'll need to make them yourself out of anything you want.  Just make sure the triangles on the ends are equilateral.  The other dimensions tie the 2 triangles together and if both pieces match, you'll be good to go.

Make a pair of these, solve the puzzle and win a year's pro membership.  I'll send a badge to everyone who publishes a picture (until I run out).  I really don't know what badges are, except for the kind in Blazing Saddles, but I have a bunch of them and I'd like to give them away to people who make stuff.

Good luck to everyone.

Step 2: Come On...

Picture of Come On...

For cryin out loud... I said MAKE them, not CG or draw them.  The first person who sends me a PHOTO of a set of these will win.  Don't just send the drawing or graphic in... Take the next step and make something that you can carry with you.

As of early 6/21/12, the prize is still up for grabs.

Step 3: All Done

Picture of All Done

All of the prizes (even those I've decided needed to be awarded after the fact... Having your own contest with your own rules has it's perks) have been awarded and I don't have any available memberships left.  If I get more, I'll most likely give them away, for this, or some other, unofficial contest.  Hope you have enjoyed it.

If you like this Instructable and would like to carry around easy access to more of my "stuff", you can download my mobile phone app at:

Ain't technology great? :-)


darrenah (author)2017-02-06

Can I still win a Pro Membership for a year? Because I can solve this puzzle.

FrozenIce (author)2012-09-28

DARN IT!! One look at the first picture and i knew the answer!!! AAAHHHH i will go mad.... okay back to sanity, it is too late to enter. Will you be making more of these challenges? Please, please please! Very smart, too :)

bfk (author)FrozenIce2012-09-29

Thanks Frozenice (I really like your user name), I've given away several memberships, but haven't been as active here of late. I've been doing more over at "" since it relates directly to 3D printing, which I've been doing a lot of.

I'm beginning to use the printer more for making parts for my latest project (which I can't seem to be able to add a photo of here). Maybe I can do a couple of instructables around it and have another contest. They are fun to do.

azharz (author)2012-08-10

Just do it yourself because my camera is not working properly.

azharz (author)2012-08-10

Just keep both face to face and rotate one of the piece in 90 d the puzzle is solved

smeet199 (author)2012-07-05

Can u keep one more compitition please keep

DoctorDv (author)2012-06-30

It would probably work if you took one that is larger than the other one and put one of the smaller shapes faces onto the larger shapes faces and keep messing around until you get a pyramid. I've been thinking about this for awhile and it seems to work in my brain! I don't have access to a 3d printer so I cannot print one. Cool illusion though!


bfk (author)DoctorDv2012-07-04

Thanks for your response David. Sorry for my delay, but I've been out of town. You don't need a 3D printer to make one of these. This one was made from rosewood.

Grey_Wolfe (author)2012-07-02

I didn't see this challenge till just now. I instantly was trying to come up with a paper folding pattern because I don't have a 3D printer. :(

Too bad the challenge is over, I wouldn't mind me some Pro Membershipness. lol

bfk (author)Grey_Wolfe2012-07-03

Gee guys, I wish I could hand out memberships to everyone who responds, but I'm not associated with Instructables and have to earn them like everyone else. I need to save a few for other things. If you post your own Instructables, you can begin collecting your own memberships and giving them to folks who'd benefit.

I just returned from a trip and took a couple dozen pyramid puzzles with me and handed them out to everyone from kids' parents (don't give them directly to children who don't know you) to waitstaff. Everyone appreciates small gifts and bowled over when they're from complete strangers and awed by the difficulty of this seemingly simple puzzle.

smeet199 (author)2012-07-02

i borrowed it from my small brother

smeet199 (author)2012-07-02

can i get membership now

Wellsinator (author)2012-06-29

This is the first page I visited on this site!

So, I saw the challenge while at my podium at work, designed and constructed the pieces within twenty minutes (paper and scotch tape), and solved the puzzle in about ten seconds.

Such a fun challenge! Wish I had come to this site earlier in my life, so amazing!

bfk (author)Wellsinator2012-06-29

Thank you for your great comment and the pictures of your puzzle. And because this was the first page you came across on instructables and because you actually made the puzzle, I'm sending you a 3 month. Pro membership. This is your lucky day:-)

Pranavthegreat (author)2012-06-27

no when i was small i got it in a chips pack

Pranavthegreat (author)2012-06-26

here it is!!!!!!!!!!!

bfk (author)Pranavthegreat2012-06-26

Beautiful! And for all your trouble getting it to me, I'll send you a 3 month pro membership as well!

Is that printed? I made one like that (in black) that's been polished up and looks pretty good, but yours has finished edges and everything. NICE work!

the dashing hero (author)2012-06-26

hello, is it too late to enter?

bfk (author)the dashing hero2012-06-26


Yes it is, but I'll send you a 3 month membership for being 2nd!

It looks good. Did you make it out of paper?

sahilverma (author)2012-06-24

Hi I am sahil verma from India ( 16 yrs old)
I would like to state that there is one fool proof method .
This is BRUTE FORCE ( Its the method that can even be programmed into a robot in order to solve puzzles)
The only pre requisite is a little bit know-how of permutations and combinations.
how this works is like this :-
each peice has 5 sides so the total number of possible arrangements is 5x5=25 . So its a sure shot way to figure out the answer in 25 chances .
ONE of the 25 permutations is the answer.

bfk (author)sahilverma2012-06-25

Hi Sahil Verma:

Thank you for your insightful comment! Because you are thinking, I'm sending you a patch.

There is one flaw with your solution. What your propose is correct IF all of the sides could fit the other sides only one way (like a jigsaw puzzle).

The sides of these shapes are completely flat, therefore they can each be rotated to any degree and placed against another side, which in turn can be rotated to any degree, creating an infinite number of possible combinations.

Of course, people do not place the shapes together and say to themselves, "hmm, that didn't work", and then, rotate one of the pieces a few degrees and say "hmm, that didn't work".

But in this puzzle's case, the two square sides need to be placed together (and because of that optical illusion thing I've mentioned, those sides usually get put together so the pieces are facing the same direction) and then one of them needs to be rotated 90 degrees.

I like the way you think, because of all the comments so far, you are the only one who has tried to explain the solution scientifically. Keep up the good work, and maybe someday we'll hear about you in your career, whatever it is you decide you'd like to do. (hint: Physics is nice).

And because you are the only one who has tried to explain the solution scientifically, I'm also sending you a 3 month pro membership!


sahilverma (author)bfk2012-06-25

Yeah ! I too figured out the direction issue in the placement of the pieces which will exponentially increase the number of permutations, but couldnt add that in my comment as my mom was after me " switch of the computer at ONCE !" haha!!
AND THANKS ALOT for the PRO MEMBERSHIP !!!! yaaaaaayyyy !!!!!
you just made a 16 yr old occupied for 3 months !!!!

Thanks again !

Pranavthegreat (author)2012-06-25

how can i post my picture

bfk (author)Pranavthegreat2012-06-25

At the bottom of the comment box, directly under the "be nice" notice, there's an "add images" box. Click that and it will allow you to select what you want to post from your computer and then, upload it to your "library" where you can add it to your post

Pranavthegreat (author)2012-06-23

thnxx for the measurement but how can this triangle??

bfk (author)Pranavthegreat2012-06-24

This is a pyramid cut exactly in half. Each piece has 2 triangles. Look at the drawings others have posted to see how they fit together. I am a little confused by your question. Please ask again with different words. I want to make sure you are getting the right answer from me.

Pranavthegreat (author)2012-06-23

i know how to make it but i just need its layout of it

bfk (author)Pranavthegreat2012-06-23

What do you mean by "layout"? The only dimensions missing in the drawing are the angles (assumptive Sketchup limitations), but they're all 30º, 60º or 90º and it's easy to figure out which are what.

If I'm missing something, I'll add it.

Hawkeye_bkj (author)2012-06-20

Unfortunately, I don't have have access to a 3d printer and haven't built one yet either. So to show the solution, I modeled it and have an exploded view.

bfk (author)Hawkeye_bkj2012-06-20

Nice graphics Hawkeye. Don't worry about a printer. I didn't have a printer either when I was designing and patenting ideas for decades. I used to make prototypes by hand with the same slicing technique these printers use (with .020 styrene). The results were far better than printed. The down side was it took tons of time to make every prototype. The printers aren't speed demons either, but the advantage is, I can design something, send it to the printer, go back inside, sit on my butt. watch TV and eat ice cream.

In 10-15 years, everyone will have one. Businesses will probably give them away... Here's why:

Mr. businessman wants to sell product, so he spends the money to buy materials, have tooling built and product made. Then, this product needs to be packaged and shipped back to his warehouse where it sits on a shelf . Mr. businessman has just spent a lot of money in the hopes someone comes along and wants it. Meanwhile, he's still spending money to store it.

Now, if all his potential customers had a 3D printer, all he would have to do is store his product on his server. When someone wants one, they pay hime via PayPal and he sends them the code to print it out. He doesn't even have to spend money on materials, packaging or shipping. The customer supplies all of it. For the businessman, it's 100% profit. For the customer, it's 100% instant gratification, like downloading an app or a song.

Right now, we're in the Stanley Steamer / Model-T era of these printers, even though slicing technology has been around since the 1970s.

The longer you wait to get a printer, the better your prints will be. Try using the slicing technique or, if you use a program like Sketchup, the folding technique.

Brandon23z (author)bfk2012-06-22

you are so damnnnn funny! at first i thought you were being serious then i was like no thats not possible, who does the slice method when they dont have a 3d printer? dude that was hilarious

bfk (author)Brandon23z2012-06-22

Actually, slicing was used in the 1970s when auto manufacturers needed to get prototypes quickly from their suppliers. The supplier would "slice" their drawings and fax them (faxes were a "new" technology, back then) to Detroit where the engineers would cut the shapes out and glue them together, just like a 3D printer does today.

All technologies are offsprings of earlier technologies. If the inkjet printer and plotter hadn't been invented, we most likely wouldn't see fused deposition printers today. I'm not saying there wouldn't be 3D printing, just not fused deposition 3D printing. Why? Because all the knowledge about X-Y printing wouldn't have been available to the designers and inventors of 3D printing technology. They would move toward the most understood technology available to produce the results they wanted. Maybe stereo lithography lasers (laser printers) would have been the most cost effective way to produce a solid object today.. Who knows? We all could be knee-deep in resin... And you thought changing your own ink is messy:)

Bottom line, I may be funny, but I'm dead serious about technologies and how we got where we are today.

But thanks for the comment. I mean that. You just gave me an idea for an instructable.

alindsey3 (author)2012-06-21

did someone already win?

bfk (author)alindsey32012-06-22

Sure did... But don't let that stop you, make a pair and have some fun.

mathlas (author)2012-06-18

I made my own template and printed on carton

smessud (author)mathlas2012-06-18

Old tech

bfk (author)smessud2012-06-21

I don't think this is old tech. This looks like a CG image that is very photographic looking, but I need someone to make a physical set... Not too cool showing your buddy an image of the puzzle and saying "Bet you can't figure this out".

Technology is great, but we still operate in the real world... Make me a physical puzzle.. How hard can it be?

But yes, sometimes the old way will beat out the new... I suspect that may still happen here.

Make it out of putty, send me the photo and you'll win... Cheeeeese

mathlas (author)bfk2012-06-21

I don't have any putty, but I assure you that it is real, I printed it on 185g carton and glued it together. Here another photo with other REAL stuff :)

mathlas (author)mathlas2012-06-21

And some more photos from different angles

bfk (author)mathlas2012-06-22

Congratulations Mathlas!

I will PM your pro membership to you ASAP!!!

Nice job on those pieces :)

Xolin (author)bfk2012-06-21

Mathias has obviously made a "Real" version of the puzzle...So are you going to award him the prize..?

bfk (author)mathlas2012-06-21

Is this CG? If not, you win, but I don't think it's a real photo. If it is CG of carton, why don't you make it?

rickharris (author)2012-06-19

Have made this many times in card and wood. I used to use it as an introduction to nets and forming 3 D objects out of 2 D material. Good drawing practice as well

bfk (author)rickharris2012-06-21

I love this puzzle. I bought one in the 1950s at a magic store and have used it to show how difficult a seemingly simple task can be. No, I can print out as many as I want. Ya gotta love technology.

Aegian2424 (author)2012-06-21

why did you consider this to be difficult?

bfk (author)Aegian24242012-06-21

Hi Aegian 2424

This is difficult because your subconscious sees the square portion as an optical illusion. Looking at the piece, the triangles sticking off of the ends, make the square look like a rectangle. Your subconscious, much like modern managament at most companies, won't tell you "Hey, you're looking at an optical illusion", but tells you that what you're looking at is a "rectangle" and rotating the pieces won't work because 2 rectangles only fit together one way.

Of course, the only way I can prove this to you is for you to make a pair and watch as your friends struggle to figure them out. If you're quick, you can also win yourself a year's pro membership... No one has made them, photographed them and posted the photo. So far, everyone has made drawings and CG images, so the contest is still waiting to be won.

About This Instructable




Bio: Old inventor, reverted back to my 10 year-old self. A shop full of tools, a boat, race car, 3D printer and a beautiful wife who ... More »
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