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Penrose Triangle

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Forum topic by BearUK posted 05-02-2016 07:04 PM 931 views 1 time favorited 24 replies Add to Favorites Watch
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BearUK

10 posts in 215 days


05-02-2016 07:04 PM

Topic tags/keywords: question

I am a novice starter and a friend gave me a Penrose Triangle to copy. I have made several now (With just as many boo-boos) Can anyone explain to me why they shrink after a while. I am using mahogany, maple, birch predominantly.


24 replies so far

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JBrow

817 posts in 381 days


#1 posted 05-05-2016 03:20 AM

BearUK,

With little info to go on, I assume the build is three pieces of wood attached one to the other. If the pieces of wood lose moisture over time, the wood will shrink mostly along it width and thickness, not much shrinkage along it length. The amount of shrinkage would increase as the width and/or thickness increase as well as if the project were made from un-dried lumber.

If the project absorbs moisture after built, it will increase in size along its width and thickness.

Applying a finish will help reduce the lose or gain of moisture, but will not eliminate it, but it may help enough to maintain the illusion.

Another problem that could perhaps give the appearance of shrinking Penrose Triangle (PT) could be in the joinery. If the joints slip even just a little, perhaps it would be enough to cause the PT to appear as if the wood has shrunk. But I am not sure the joint hypothesis would account for the affect you are seeing.

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jerryminer

528 posts in 902 days


#2 posted 05-05-2016 05:15 AM

Can you post a pic?

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BearUK

10 posts in 215 days


#3 posted 05-06-2016 12:16 PM

The wood is dried, I apply a coat of Danish Oil and then run the 3 step process through the Beall buffer. Not able to send a picture at this time, do not have capability, but will have friend do later. Thanks for responding…

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bondogaposis

4024 posts in 1812 days


#4 posted 05-06-2016 12:57 PM

Impossible to answer with some pictures of what you are trying accomplish.

-- Bondo Gaposis

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BearUK

10 posts in 215 days


#5 posted 05-06-2016 01:32 PM

will be seeing someone tomorrow with capability, will have him post photo…

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ArtMann

131 posts in 277 days


#6 posted 05-06-2016 01:59 PM

The Penrose triangle is an impossible shape made famous by artist M. C. Escher. I would like to see a photo of how you made it.

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BearUK

10 posts in 215 days


#7 posted 05-06-2016 02:13 PM

I believe there are already photos on this site, just do a seach and I am sure you will find them…

View RogerM's profile

RogerM

759 posts in 1860 days


#8 posted 05-06-2016 02:25 PM

Definition of Penrose Triangle – An optical illusion depicting an impossible solid object made of three straight beams of square cross section which meet pairwise at right angles at the vertices of the triangle they form.

-- Roger M, Aiken, SC

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Rick M

7907 posts in 1841 days


#9 posted 05-06-2016 04:47 PM



I believe there are already photos on this site, just do a seach and I am sure you will find them…

- BearUK

You’re asking for help, link to the pictures. Is this is an inlay?

-- http://thewoodknack.blogspot.com/

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Picklehead

1015 posts in 1390 days


#10 posted 05-06-2016 06:37 PM


I believe there are already photos on this site, just do a seach and I am sure you will find them…

- BearUK

You re asking for help, link to the pictures. Is this is an inlay?

- Rick M.

Here are a few links:

1
2
3

-- You've got to be smarter than the tree.

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Rick M

7907 posts in 1841 days


#11 posted 05-06-2016 08:59 PM

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Picklehead

1015 posts in 1390 days


#12 posted 05-06-2016 10:16 PM


Those are not Penrose Triangles.

- Rick M.

Well, Rick, since the Penrose Triangle is an “impossible object” I’ll admit they’re a little camera shy, but that is what we have been referring to. Maybe you’ve got a picture of one?

-- You've got to be smarter than the tree.

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jerryminer

528 posts in 902 days


#13 posted 05-06-2016 10:23 PM



Those are not Penrose Triangles.

- Rick M.

Well—-technically, you’re right. Since a true Penrose Triangle, by definition, is an impossible object, nothing actually is a Penrose triangle. We can only create the illusion of a PT, not the actual object. As such, though, the Penrose Trivet is about as close as one can come to an accurate representation.

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Rick M

7907 posts in 1841 days


#14 posted 05-07-2016 07:24 AM



Well, Rick, since the Penrose Triangle is an “impossible object” I ll admit they re a little camera shy, but that is what we have been referring to. Maybe you ve got a picture of one?

- Picklehead

Settle down. If someone asks for help, it’s their job to articulate the question clearly; not mine to do riddle out what the meaning. The guy could have said off the bat he is making trivets. Clearly no one above knew what he was talking about until you posted pictures and even then I wasn’t sure because you didn’t answer his question.


Well—-technically, you re right.
- jerryminer

Well if you guys know what he’s talking about, why didn’t you answer the question?

-- http://thewoodknack.blogspot.com/

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jerryminer

528 posts in 902 days


#15 posted 05-07-2016 06:11 PM



Well if you guys know what he s talking about, why didn t you answer the question?

- Rick M.

Why? Because we don’t really know what the issue is yet (other than “shrinking”). We don’t know that the OP is making trivets like those Picklehead linked to, or possibly marquetry projects, or something else.

Bear UK: can you tell us?

I suppose, as a general answer, I can say that wood shrinks when it loses moisture, but I’m hoping for a more specific question in order to provide a more specific answer.

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