Re: naive questions regarding isometries

From: Sean McIlroy (sean_mcilroy_at_yahoo.com)
Date: 11/24/04 

Date: 24 Nov 2004 00:11:05 -0800

> A mirror image switches the "handedness" of a figure, but doing it a second
> time switches it back.

So: Figures have a certain property with two possible values, and two
figures have different values for that property if one can be obtained
by reflecting the other. I was hoping for something a little more
informative, in particular some kind of proof.
 
> >*) What conditions determine whether a two dimensional figure can be
> >rotated and translated back to itself after being subjected to a
> >reflection?

> ... the figure would
> need to be bilaterally symetric (congruent with at least one reflection of
> itself).

So: After being reflected, the figure can be rotated and translated
back to itself if it's congruent with its reflection. Also not as
informative as I was hoping for.

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