"Examine your own hearts. Do you see there any habit or custom which you know is wrong in the sight of God? If you do, don't delay for a moment in attacking it. Resolve at once to lay it aside. Nothing darkens the eyes of the mind so much, and deadens the conscience so surely, as an allowed sin. It may be a little one, but it is not any less dangerous."

Previous Quote

Speaking about symmetry, look out our window, and you may see a cardinal attacking its reflection in the window. The cardinal is the only bird we have who often does this. If it has a nest nearby, the cardinal thinks there is another cardinal trying to invade its territory. It never realizes it is attacking its own reflection. Cardinals don't know much about mirror symmetry!

— Martin Gardner