Introduction: Modular Pie-cosahedron

Picture of Modular Pie-cosahedron

constructing a pie with the topology of a sphere from 20 triangular sub-pie modules attached with amazing magnets.

Step 1: Layout and Cut the Pieces

Picture of Layout and Cut the Pieces

we needed 20 equilateral triangles. choosing an altitude of 12 inches let us easily lay out two strips of them on a 24x48 inch sheet of 24 gauge steel. in order to get the dihedral angle at which the sides of the pans have to meet to form the whole icosahedron requires the sides to be sloped at darn near 120 degrees so if one just cuts out the diamond shaped tab in each corner, the results fit together quite nicely.

we decided to pick up a power-shear from harbor freight. cuts the sheet like butter and leaves a cleaner edge than the hand sheers. it wouldn't work for really detailed work but for reasonably smooth curves it's definitely worth it's weight and even for straight cuts it's significantly more affordable than a floor shear.

Step 2: Fold and Rivet the Sides

Picture of Fold and Rivet the Sides

folding the pans was greatly simplified by a 18inch bending brake. when you have to repeat some step 3*20 times, it's definitely worth setting up the appropriate jig. here a piece of metal to clamp down the pan was cut to give the appropriate clearance and later re-used as a hold down for drilling. we used a pop rivet in each corner to hold things a bit more rigid.

remember that sheet metal is sharp. wear gloves, but don't be afraid to have fun.

Step 3: Attach Magnets

Picture of Attach Magnets

at this point, we thought it was time to glue the magnets on. we wanted to use 6 magnets (aquired from to join each edge. interestingly enough, if you attach all six magnets to one side of each edge, you end up having to make some pans where two edge are lined with magnets and some pans where only one edge has magnets, a direct consequence of the so called "hairy ball theorem". the lack of symmetry is unsatisfying to say the least but has an easy solution. rather than trying to orient each edge, orient the pan, split the magnets so there are 3x3 on every pan and offset the magnets counter clockwise.

Step 4: Baking a Test Pie

Picture of Baking a Test Pie

it was time to bake a test pie. the doubters needed to know for sure that the pie would stand up to inversion. the answer was that, "yes it did". more importantly, the experiment showed was that the 350 deg F was plenty beyond the curie point and essentially voided our magnetic attachment scheme. it was now time to weep while we "un-epoxied" 180 magnets.

Step 5: Baking 19 More Pies

Picture of Baking 19 More Pies

gathering ingredients to make 20x pecan pies is still exciting, even after all these years. we used the recipe on the back of the karo bottle and added 1.5 tablespoons of flour to help guarantee the pies weren't overly runny.

the modular construction of the pie-cosahedron was a godsend in terms of cooking preparations. we pipelined 4 sub-pies per shelf in the oven, hit em with 75 minutes of baking at 350F and cooled on the counter-top while the next 4 went in.

remember to line the bottom of the oven with foil. things are likely to run over and the sugar burns on hard.

Step 6: Re-epoxy Magnets

Picture of Re-epoxy Magnets

once the pies were cool, we re-attached the magnets. it is a little hard to describe accurately the sensation of wrestling with magnets that are incredibly small, incredibly powerful and covered with some combination of pie filling and rapidly hardening epoxy. let's just say i wouldn't spend the night before thanksgiving any other way.

Step 7: Assemble Pie and Enjoy

Picture of Assemble Pie and Enjoy

we wrapped each sub-pie-assembly in saran wrap to make it easier to transport and put together. the saran wrap was cut off once the pies were in place and ready to be served. there was surprisingly little slump; the layer of pecans and crystallized sugar did well to hold in the gooey interior. on whole the pie consistency was judged to be far better than that of the fractal pie, probably due to the deeper pans and more controlled cooking process.


canida (author)2008-11-24

This project was featured on NPR's Here & Now on Monday, November 24 2008!

smartmiltoys (author)2015-02-24

Really very interesting!)))

patsheldon (author)2014-03-03

omg over the toppp!! I wanna party with you guys! ;D

Laughinggamer (author)2014-02-05

This would be GREAT for brownies! Fantastic idea and construction.

ilpug (author)2011-03-19

you need to supersize this. now that you have a modular building system you can make anything!

mememememememe (author)2007-11-21

But pie are squared!

This made me rofl. Brilliant :)

ilpug (author)pirateykris2011-03-19

pie can be squared easily, with a sharp knife.

pyearick (author)mememememememe2010-11-21

No, pie are round. Cornbread are squared.

hahaha!!! ROFLPMP!!!:D

WYN soldier (author)2010-11-22

haha the idea is great now make the oven that comes with it XD

tubegeek (author)2010-11-21

Fractal pie?

Aswa (author)tubegeek2010-11-21
I had the same thought, so I searched. ;)

Icalasari (author)2010-11-21

Idea: Make it so that the magnet portions are a separate section. The pies get baked in pans that can hook onto the frame. Then you can do this each year if you desired without having to wrestle with magnets every time

BigCountry (author)2010-11-21

Dude!! You have WAAAAAAYYY too much time on your hands!! Cool pie, though

mshekleton (author)2010-11-21

...and then you put the sharp sheet metal on your head. lol :)

Fish_Kungfu (author)2010-11-21

Awesome job!!! What about some Phi-pie? That would be golden-ly delicious! ;-p

Brewerjp (author)2010-07-08

I can't believe this hasn't been said yet... This pie rolls a natural 20 every time!

stupidstickanimations (author)2010-03-17

i might make pizza in one of these instead :D

icecoldcelt (author)2010-03-15

I have to get/make a shirt like that. Period.

bluebeard (author)2010-03-15

I'm guessing that you used NIBs.  Samarium-Cobalt's have a higher curie point that  will survive kitchen oven temperatures.  They are the second strongest type of magnets, right behind NIB's.

rockerape (author)2010-03-14

sheet metal happens.   8P

brainmist (author)2007-11-22

I'd just like to say - and I'm not one to exaggerate - but you, sir/madam, are a GOD. That's right, I've said are clearly a minor deity at least of the juncture of geometry and pie. Geopastry, maybe. Nevermind the figuring-out-how-to-do-it, the sheer audacity of the idea merits you applause!

*erects a small shrine to Geopastronus, God of Pie and Angles (tm)*

adamvan2000 (author)brainmist2008-11-27

Surely you mean....*waits for the drum-roll* Pie-angles? :OD ~adamvan2000

evanwehrer (author)adamvan20002009-01-09

:OD <-------has a big nose!!!

1spartan95 (author)evanwehrer2009-07-30

Or if you tilt your head to the right it's Homer Simpson!

professorred (author)1spartan952010-03-14


BeanGolem (author)2010-03-14


krazipanda (author)2009-10-14

what happens when u wwant to eat it?

red-king (author)2009-08-08

omg!!! it's a pie d20!

1spartan95 (author)2009-07-30

Calling all geeks and pie lovers!!!!!

kelseymh (author)2008-11-24

Step 2: Nice T-shirt, dude! I can't quite tell if it's supposed to be vacuum corrections to e-e scattering, or Drell-Yan. Either way, sweet...

turkey tek (author)kelseymh2008-11-24

thanks! it's e-e scattering.

it was one of those visual coincidences just waiting for some crackpot
to discover:

kelseymh (author)turkey tek2008-11-24

Truly, truly hilarious. I wonder just how many crackpots have already posted their theories about bees navigating via quantum entanglement :-/

BTW, I see that your "Berkeley" location is now UCI. Congrats on the faculty position! I didn't know Irvine was that open to cross-disciplinary work (artificial vision and Drosophila epigenetic atlases; quite the mix).

Lithium Rain (author)kelseymh2008-11-24


You mean they DON'T?!

All I've ever known is a lie...

evanwehrer (author)Lithium Rain2009-01-09

The cake is a lie!!!

1spartan95 (author)evanwehrer2009-07-30

No, it's a truth that you deny!

techshop1 (author)2009-07-17

You have way too much time on your hands. Wish I had time to play like that. Enjoy it while you can. Looks like a fun project - Great job!

MillenniumMan (author)2009-06-11

PIE is exactly 3! Sorry, had to get the fat nerds attention away from the buffet table and back to the conference table. Now, let's try to divide the pie by PI.

Azayles (author)MillenniumMan2009-06-22

PIE divided by Pi is 0.95492965855137201461330258023509blahblahblah Seems the nerd baiting worked :P

ItsTheHobbs (author)2007-11-06

pie and math, i dont like either but anyways this is great, and a great idea too

tanmanknex (author)ItsTheHobbs2009-06-03

you don't like pie??? How could you?!?!?! I'm taking that as a personal insult!!! (JK)

evanwehrer (author)ItsTheHobbs2009-01-09


PKTraceur (author)2008-11-25

Did you just make a D20 pie??!?!?!?!

REA (author)PKTraceur2009-05-19

this would be great for a huge D&D; party!

Weather_blue (author)PKTraceur2008-12-19

The ultimate in gamer food. I just failed my save vs. hunger. :)

hishealer (author)Weather_blue2009-04-03


Thekal (author)2009-04-14

Your ONE triangle away from a FULL trio of triforces.. power courage wisdom

spiffytessa (author)2009-03-15

The awesomeness of this has left me speechless.

About This Instructable




Bio: thanksgiving! ...and bringing technology to this traditional celebration of excess.
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