wrote:
Carl Fogel wrote:

http://www.niquette.com/puzzles/cornrefp.htm

Cheers,

That item is interesting in a few ways. Unlike optical engineers, the
writer chooses to call a "cube corner" (trihedral) reflector, a
"corner cube" in a jargon that should include "shell eggs" instead of
"egg shells", or "tread tires" instead of "tire treads" as is common
in English for compound words. This is often a flag that something
else going on than rational discussion.

If you Google the terms "corner cube" and "cube corner" you'll find that
both are used to reference retroreflectors, but "corner cube" is the
more popular term. When I did laser interferometer application design
the term used was "corner cube".


Beyond that, the writer is apparently unaware that road signs, Botts
dot lane dividers, and spot reflectors, those 3-inch round, red,
yellow, and blue plastic reflectors in a two screw hole metal frame
use cube corners and serve well as safety devices. Overlooked is that
these cube corners do not have perfect 90° corners so they reflect a
diverging beam that does not go only back to the light source. If
that were not so, road markings wold not be visible in headlight
beams.

Indeed, that was the "solution" to the "puzzle". That the problem was a
"puzzle" reflects the author's unfamiliarity with optics more than
anything else.

These "gotcha" problems to me often reflect badly on the posers. In his
explanation he says: "The query in the puzzle calls for an explanation,
which will be elementary for a sophisticated solver who understands how
a Corner Cube works". So, the fact that he was surprised by the failure
of his retroreflector must be explained either by his "unsophistication"
at problem solving or his ignorance of retroreflectors. Presumably it's
the latter since he seems to regard himself a very clever fellow. If so
clever, why does he attempt to use things without a basic understanding
first? It's just plain vanilla ignorance on his part, which he also
presumes of his audience.