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Subject: 
Re: Chirality
Newsgroups: 
lugnet.build.schleim, lugnet.parts
Date: 
Fri, 9 Sep 2005 16:27:46 GMT
Viewed: 
5126 times
  
Hey,

Awesome post! Larry has a point with the text on the studs, but when I teach symmetry and chirality and talk about everyday objects I always put in the caveat “this baseball has such-and-such symmetry properties, igoring all imperfections and this text over here”.

Which, of course, leads to an expansion on Didier’s original post, you can describe the symmetry properties and point groups of each brick. For instance, a 2x4 brick has two planes of symmetry (that is, you can divide it in half either between two 2x2 fragments or between two 1x4 fragments and the two halves are mirror images of eachother) and a C2 axis (that is, you can rotate it 180 degrees along an axes parallel to the direction of the studs and get the same thing), so it is in the C2V point group. A 2x2 brick is in the C4V point group. A 2x2x1 slope is Cs, and so forth.

A stack of bricks is sort of like a crystal structure, with a repeated pattern of unit cells. It turns out that molecules of certain point groups will fit into certain types of crystal lattices, while others will not. Or sometimes chiral molecules will fit into certain crystal lattices only when paired with their enantiomers. In the same way certain bricks will stack to form certain types of repeated structures, whereas others will not, or perhaps certain forms will work if you pair up chiral bricks with their enantiomers etc.

Speaking of repeated patterns, I found this from Brickfest to be an interesting demonstration of this.

Bruce



Message has 1 Reply:
  Builder's Block Crystal Lattice (Was Re: Chirality)
 
(...) I was contemplating the above, while I was sorting a bunch of these: (URL) So I made a couple of chiral bits: (URL) Which go together to form a roughly cubic shape and its enantiomer: (URL) Yet they also apear to be achiral if you orient them (...) (19 years ago, 26-Sep-05, to lugnet.build.schleim, lugnet.parts, lugnet.announce.moc, FTX)  

Message is in Reply To:
  Chirality
 
LEGO and chirality Chirality is the property of an object that can not be superimposed on its mirror image. Examples includes both natural (biological) object such hands and cultural (technical) object such screws. A non-chiral (achiral) object can (...) (19 years ago, 8-Sep-05, to lugnet.build.schleim, lugnet.parts) ! 

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