# Reflecting on spoons. **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [October 12, 2004, 3:29am UTC](https://boards.straightdope.com/t/reflecting-on-spoons/268768 "2004-10-12T03:29:22Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![sturmhauke](https://avatars.discourse-cdn.com/v4/letter/s/e47c2d/32.png) [@sturmhauke](https://boards.straightdope.com/u/sturmhauke)\ **Post date:** [October 12, 2004, 3:29am UTC](https://boards.straightdope.com/t/reflecting-on-spoons/268768/1 "2004-10-12T03:29:22Z")
[http://www.straightdope.com/classics/a2\_082.html](http://www.straightdope.com/classics/a2_082.html) > [@Cecil](#): > > We thus have a remarkable thing: a mirror that, in contrast to standard mirrors, reverses up and down but not left and right. Well, not exactly. What actually happens is that the image is reversed left to right and rotated 180 degrees. If you hold something with text upside down, it will appear in the spoon right side up but backwards. ---
**Author:** ![Askance](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/askance/32/8281_2.png) [@Askance](https://boards.straightdope.com/u/Askance)\ **Post date:** [October 12, 2004, 5:27am UTC](https://boards.straightdope.com/t/reflecting-on-spoons/268768/2 "2004-10-12T05:27:51Z")
And, at least according to [Martin Gardner](http://www.rain.org/~mkummel/stumpers/24oct03a.html), a standard mirror does \*not \*reverse left and right - what it does is reverse front and back (assuming you are facing it or facing directly away from it). ---
**Author:** ![Greg\_Charles](https://avatars.discourse-cdn.com/v4/letter/g/839c29/32.png) [@Greg\_Charles](https://boards.straightdope.com/u/Greg_Charles)\ **Post date:** [October 12, 2004, 10:04am UTC](https://boards.straightdope.com/t/reflecting-on-spoons/268768/3 "2004-10-12T10:04:42Z")
Cecil had been told about these “right facing” mirrors, but 17 years on now, has anyone actually seen one? I suppose it would look something like a section of a cylinder as seen from the inside. Would that work? I’ve seen the relection of my reflection, which sort of amounts to a right facing mirror too. The problem was you had to look sort of sideways at it. ---
**Author:** ![Meeko](https://avatars.discourse-cdn.com/v4/letter/m/e495f1/32.png) [@Meeko](https://boards.straightdope.com/u/Meeko)\ **Post date:** [October 12, 2004, 12:09pm UTC](https://boards.straightdope.com/t/reflecting-on-spoons/268768/4 "2004-10-12T12:09:02Z")
An Interesting aside: The nearly classic “spoon boy” scene in “The Matrix” has commentary on spoon reflections. I have both the DVD, and the 60 dollar “The Art of The Matrix” coffee table book. One or the other, if not both discusses how they (the directors) considered editing the shot, away from the standard reversals, in order to maintain (some) credibility among the main public. They thankfully decided against it, in the final versions. But “there is no spoon” so what are we talking about anyway? 🙂 ---
**Author:** ![sturmhauke](https://avatars.discourse-cdn.com/v4/letter/s/e47c2d/32.png) [@sturmhauke](https://boards.straightdope.com/u/sturmhauke)\ **Post date:** [October 12, 2004, 4:20pm UTC](https://boards.straightdope.com/t/reflecting-on-spoons/268768/5 "2004-10-12T16:20:07Z")
> [@Greg Charles](#): > > Cecil had been told about these “right facing” mirrors, but 17 years on now, has anyone actually seen one? I have one in my bathroom. It’s a medicine cabinet with a main mirror and two side mirrors on hinges. If you set one of the side mirrors at a right angle to the main mirror and look at the intersection, you will see yourself as the world sees you. ---
**Author:** ![Assuming\_facts\_not\_in\_evidence](https://avatars.discourse-cdn.com/v4/letter/a/e9bcb4/32.png) [@Assuming\_facts\_not\_in\_evidence](https://boards.straightdope.com/u/Assuming_facts_not_in_evidence)\ **Post date:** [October 12, 2004, 8:24pm UTC](https://boards.straightdope.com/t/reflecting-on-spoons/268768/6 "2004-10-12T20:24:11Z")
The problem with the two-mirror solution to “right facing” is the line up the middle where the mirrors come together. If you shift the mirrors to slightly less than 90º you can see yourself with your eyes shiftily glancing to the side. There’s the problem of error as well, on glass bathroom mirrors, as there is a ghost image from the front side of the glass, which is reflected on both the mirror and the other glass front, giving you a reflection that has 3 ghosts. Even without the glass you have two mirrors. This is unlike the spoon. It should be possible mathematically to describe a surface more like a spoon, where each ray is reflected once, not twice. Ususally these puzzles are worked in reverse by computer, calculating one mirror segment at a time. You define the rays you want to arrive at the eye, in terms of 3-D direction, and place the mirror at that point such that you get the reflection you want. There are lots of possible location for that mirror point. Do that for adjacent points, keeping the distances (image size) constant. Easy to conecive, but perhaps hard to manufacture. For all I know, the result might look like a Fresnel lens, or a quadratic spoon with almost no tolerance for error. And having no particular valuable purpose, it’s not going to get much research money. ---
**Author:** ![nitpick](https://avatars.discourse-cdn.com/v4/letter/n/e99b99/32.png) [@nitpick](https://boards.straightdope.com/u/nitpick)\ **Post date:** [October 13, 2004, 1:59am UTC](https://boards.straightdope.com/t/reflecting-on-spoons/268768/7 "2004-10-13T01:59:03Z")
Images in the concave side of a spoon aren’t always upside down. If one holds it close enough, the image will be right side up and magnified- just like a woman’s make-up mirror. The convex side will always render a right side up, distorted, smaller image. ---
**Author:** ![jackelope](https://avatars.discourse-cdn.com/v4/letter/j/a6a055/32.png) [@jackelope](https://boards.straightdope.com/u/jackelope)\ **Post date:** [October 13, 2004, 4:25am UTC](https://boards.straightdope.com/t/reflecting-on-spoons/268768/8 "2004-10-13T04:25:36Z")
> [@AndrewT](#): > > And, at least according to [Martin Gardner](http://www.rain.org/~mkummel/stumpers/24oct03a.html), a standard mirror does \*not \*reverse left and right - what it does is reverse front and back (assuming you are facing it or facing directly away from it). Damn you, Martin Gardner! A few years ago I found myself wondering _why_ mirrors switch left and right but not top and bottom. After much brain-twisting cogitation I finally figured it out. I was all set to come in here and smugly point out that mirrors reverse front and back, not left and right, and _I’ve been beaten to it_! Drat. ---
**Author:** ![AskNott](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/asknott/32/5790_2.png) [@AskNott](https://boards.straightdope.com/u/AskNott)\ **Post date:** [October 13, 2004, 4:53am UTC](https://boards.straightdope.com/t/reflecting-on-spoons/268768/9 "2004-10-13T04:53:11Z")
Martin Gardner (is that really how it’s spelled?) gets that a lot. If you turn the spoon so it is level with the ground (if your head is) does it reverse right to left, or top to bottom, or inside to outside? Can you see the ground from where you are? ---
**Author:** ![sturmhauke](https://avatars.discourse-cdn.com/v4/letter/s/e47c2d/32.png) [@sturmhauke](https://boards.straightdope.com/u/sturmhauke)\ **Post date:** [October 13, 2004, 5:47am UTC](https://boards.straightdope.com/t/reflecting-on-spoons/268768/10 "2004-10-13T05:47:45Z")
I actually have a Gardner book where he explains about the mirror thing, but I forgot about it until this thread. Gardner rules. ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [October 14, 2004, 10:39am UTC](https://boards.straightdope.com/t/reflecting-on-spoons/268768/11 "2004-10-14T10:39:22Z")
I sometimes feel like I must be the only person in the world who has never thought mirrors “reverse left and right”. How is it confusing? Say you have a mirror on one wall in the house, perpendicular to the window which is to your right. You point towards the window. Which way is your reflection pointing - yes, towards the window. Still to your right. It’s not swapping over ---
**Author:** ![RM\_Mentock](https://avatars.discourse-cdn.com/v4/letter/r/e274bd/32.png) [@RM\_Mentock](https://boards.straightdope.com/u/RM_Mentock)\ **Post date:** [October 14, 2004, 6:40pm UTC](https://boards.straightdope.com/t/reflecting-on-spoons/268768/12 "2004-10-14T18:40:45Z")
> [@Greg Charles](#): > > Cecil had been told about these “right facing” mirrors, but 17 years on now, has anyone actually seen one? They’re sold on the internet (natch 🙂 ). There is a link in a [previous thread about the column](http://boards.straightdope.com/sdmb/showthread.php?t=279820). ---
**Author:** ![lee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lee/32/7455_2.png) [@lee](https://boards.straightdope.com/u/lee)\ **Post date:** [October 14, 2004, 8:14pm UTC](https://boards.straightdope.com/t/reflecting-on-spoons/268768/13 "2004-10-14T20:14:27Z")
helical mirrors sold as christmas decorations seem to reflect an image rotated 90 degrees to the right or left depending on the twist of the ornament. ---
**Author:** ![sturmhauke](https://avatars.discourse-cdn.com/v4/letter/s/e47c2d/32.png) [@sturmhauke](https://boards.straightdope.com/u/sturmhauke)\ **Post date:** [October 15, 2004, 12:01am UTC](https://boards.straightdope.com/t/reflecting-on-spoons/268768/14 "2004-10-15T00:01:23Z")
> [@RM Mentock](#): > > They’re sold on the internet (natch 🙂 ). There is a link in a [previous thread about the column](http://boards.straightdope.com/sdmb/showthread.php?t=279820). It’s the same as my bathroom mirror, except it costs $150. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [October 15, 2004, 3:45pm UTC](https://boards.straightdope.com/t/reflecting-on-spoons/268768/15 "2004-10-15T15:45:16Z")
> [@sturmhauke](#): > > It’s the same as my bathroom mirror, except it costs $150. Apparently it uses _front-surface_ mirrors, unlike your bathroom mirrors whose _back_ surfaces are coated for reflection. With front surface mirrors, the line in the middle (where the two mirrors meet) would be much thinner. ---
**Author:** ![sturmhauke](https://avatars.discourse-cdn.com/v4/letter/s/e47c2d/32.png) [@sturmhauke](https://boards.straightdope.com/u/sturmhauke)\ **Post date:** [October 15, 2004, 8:06pm UTC](https://boards.straightdope.com/t/reflecting-on-spoons/268768/16 "2004-10-15T20:06:16Z")
Hey, if you want to pay $150 for that thing, I’ve got some [prime waterfront real estate](http://www.catzeyephotography.com/JPG/the%20swamp.jpg) to sell you.