Field Guide to Math in Humboldt 
No 32   Reflections in Math 

My very least favorite sign in Fortuna, CA.  It glaringly greets you as the first impression coming off the freeway from the north,  but it does show reflection.   
From mathbitsnotebook.com:  "A reflection is a kind of transformation. It is basically a 'flip' of a shape over the line of reflection. Very often reflecions are performed using coordinate notation as they all are on this page. The coordinates allow us to easily describe the image and its preimage."   Image also from mathbitsnotebook.com 
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