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Old July 6th 09, 09:36 PM posted to rec.bicycles.tech
Peter Cole[_2_]
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Posts: 4,572
Default Curious bicycle reflector incident

hibike wrote:
On Jun 15, 8:19 am, wrote:
Peter Cole 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 retro reflectors, but "corner cube"
is the more popular term. When I did laser interferometer
application design the term used was "corner cube".

Google is smart and knows that these backassward terms are used by
enough folks that they need search targets. It is the corner that
reflects and it is a cube corner into which light enters. When
working in retro reflectors, I was curious about the logic of the
reversed name given to the cube corner that is a trihedral corner.

I suppose people also ride bike roads and bike mountains in that
sense.





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 retro reflector must be explained
either by his "unsophistication" at problem solving or his ignorance
of retro reflectors. 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.

I don't see it as a puzzle as the writer apparently wanted to make it
seem. I guess he once looked into a laser surveyor's target and saw
only his own eye regardless of how he moved his head.

Jobst Brandt- Hide quoted text -

- Show quoted text -


Thank you for recommending that I should change the expression "corner
cube" at...

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

...to the argot of the optical engineer, "cube corner."

A Wikipedia search on "corner cube" turns up...

http://en.wikipedia.org/wiki/Corner_cube

...and a search on "cube corner" turns up no article by that name.
Perhaps you will offer an expert change via the discussion page,
which is currently blank.

Excuse me for wincing, but it is hardly collegial to imply "...that
something else [is] going on than rational discussion." Try humor.
And a satirical illustration of “Perfection est l’enemie du bien.”

Perhaps the calendar plays a part in the mystery. The self-
deprecative narrative describes events that occurred in 1972, which
possibly pre-dates the terminology as applied to both "Botts dots"
and "Scotchlite." You are invited to do the research on that.


Easy, both products were widely available long before 1972 (although I
don't know what that has to do with anything).

Meanwhile "corner cube" is the only expression I have ever heard as
a synonym for "retro-reflector," beginning with my staff
responsibilities at Electro-Optical Systems in Pasadena during the
Apollo Program.


A brief browse should acquaint you with the uses of both terms,
shouldn't take more than 10 minutes, even for a slow reader.


Best regards,
Paul Niquette

P.S. The "Corner Cube" puzzle has been quite popular, with most
people expressing appreciation for the graphic-intensive explanation.


Even with optical engineers?
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