The Physics
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Opus in profectus

Reflection

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Discussion

geometric optics

Crepuscular rays show that light travels in straight lines with relatively little diffraction.
Crepuscular rays streamind down and to the left through the woods of Thomas Jefferson's Monticello, Charlottesville, VirginaCharlottesville, Virginia Spotlights streaming upward at the Tribute of Light (2002-04-11), New York, New YorkNew York, New York Spotlights streaming from behind bronze horses atop the Grand Palais des Champs-Elysées, Paris, FranceParis, France

Pierre de Fermat (1601–1665) France, "principle of least time". Pierre Louis Maupertuis (1698–1759) "principle of least action" in 1747 or 1750? Maupertuis hoped that the principle might unify the laws of physics and support his proof of the existence of God.

The wisdom of Beekman. "We don't see things. We see light bouncing off things."

reflection

A caution sign with instruction written in mirror writing and in regular writing

A plane mirror produces only one inversion: front-to-back. This is called a perverted image. The pair of warning signs on the right illustrates lateral inversion.

The law of reflection

θi = θr