Instructables

Modular pie-cosahedron

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constructing a pie with the topology of a sphere from 20 triangular sub-pie modules attached with amazing magnets.
 
 
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Step 1: 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

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

at this point, we thought it was time to glue the magnets on. we wanted to use 6 magnets (aquired from amazingmagnets.com) 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

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

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.
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canida5 years ago
This project was featured on NPR's Here & Now on Monday, November 24 2008!
patsheldon5 months ago

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

Laughinggamer6 months ago

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

ilpug3 years ago
you need to supersize this. now that you have a modular building system you can make anything!
But pie are squared!
This made me rofl. Brilliant :)
pie can be squared easily, with a sharp knife.
No, pie are round. Cornbread are squared.
hahaha!!! ROFLPMP!!!:D
WYN soldier3 years ago
haha the idea is great now make the oven that comes with it XD
tubegeek3 years ago
Fractal pie?
Aswa tubegeek3 years ago
http://www.instructables.com/id/giant-fractal-pecan-pie/
I had the same thought, so I searched. ;)
Icalasari3 years ago
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
BigCountry3 years ago
Dude!! You have WAAAAAAYYY too much time on your hands!! Cool pie, though
mshekleton3 years ago
...and then you put the sharp sheet metal on your head. lol :)
Fish_Kungfu3 years ago
Awesome job!!! What about some Phi-pie? That would be golden-ly delicious! ;-p
Brewerjp4 years ago
I can't believe this hasn't been said yet... This pie rolls a natural 20 every time!
i might make pizza in one of these instead :D
icecoldcelt4 years ago
I have to get/make a shirt like that. Period.
bluebeard4 years ago
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.
rockerape4 years ago
sheet metal happens.   8P
brainmist6 years ago
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 it...you 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)*
Surely you mean....*waits for the drum-roll* Pie-angles? :OD ~adamvan2000
:OD <-------has a big nose!!!
Or if you tilt your head to the right it's Homer Simpson!
O:D3
BeanGolem4 years ago
 Om-nom-ahedron
krazipanda4 years ago
what happens when u wwant to eat it?
red-king5 years ago
omg!!! it's a pie d20!
1spartan955 years ago
Calling all geeks and pie lovers!!!!!
kelseymh5 years ago
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)  kelseymh5 years ago
thanks! it's e-e scattering.

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

http://images.google.com/images?q=waggle%20dance
http://images.google.com/images?q=feynman%20diagram
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).
WHAT?!

You mean they DON'T?!

All I've ever known is a lie...
The cake is a lie!!!
No, it's a truth that you deny!
turkey tek (author)  kelseymh5 years ago
techshop15 years ago
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!
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.
PIE divided by Pi is 0.95492965855137201461330258023509blahblahblah Seems the nerd baiting worked :P
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