Why Do Mirrors Reverse Left And Right But Not Up And Down?

Reflection: A transformation under which each point in a shape appears at an equal distance on the opposite side of a given line—the line of reflection. It’s not often I have occasion to shout at the television, but a recent episode of the BBC’s long-running television series QI precipitated just such an outburst. The cause … Continue reading Why Do Mirrors Reverse Left And Right But Not Up And Down? →