Wikipedia calls it the "No Symbol" [0]. ISO 7010 calls it the "prohibition sign" [1]. In Unicode, it's available as a combining character with the practical name "COMBINING ENCLOSING CIRCLE BACKSLASH" (U+20E0) [2] and in emoji form it's the "NO ENTRY SIGN" (U+1F6AB) [3].
Those date from 1993 and 2010. There's also U+26D4 NO ENTRY (2009) and U+1F6C7 PROHIBITED SIGN (2014). I wonder what the history is that we ended up with four different code points for a similar concept.
I included just the ones that were the same visual representation, U+26D4 is a different symbol. The glyph for U+1F6C7 seems to be missing in most places, I can't find an authoritative representation of it to confirm it's the same visual symbol.
EDIT: Looks like U+1F6C7 "PROHIBITED SIGN" is indeed the same symbol, as seen in the Unicode 7.0 charts [0]
> I included just the ones that were the same visual representation, U+26D4 is a different symbol. The glyph for U+1F6C7 seems to be missing in most places, I can't find an authoritative representation of it to confirm it's the same visual symbol.
I don't think that there's any meaningful sense in which two Unicode code points may be said to have, or not have, the same symbol, except in reference to a particular font. The standard just indicates some possibilities:
> The shapes of the reference glyphs used in these code charts are not prescriptive. Considerable variation is to be expected in actual fonts. The particular fonts used in these charts were provided to the Unicode Consortium by a number of different font designers, who own the rights to the fonts.
To be fair, two of the four discussed here (U+1F6AB and U+1F6C7) are early "astral plane" emoji just after Unicode gave up on Han unification as a plan and moved back to trying to better round-trip existing encodings. The existence of emoji in general is partly Unicode's mea culpa for attempting Han unification in the first place.
(It was an odd sort of apology, given most of the damage was already done and the astral plane should have probably opened up a lot sooner in hindsight, but it was a fascinating sort of apology in the way that emoji has done more for Unicode acceptance testing in first-language-English developed applications than just about any other block in Unicode history.)
Was hoping the article might shed some light on the ambiguity of some of the prohibition signs in the UK and parts of Europe, e.g. the "no motor vehicles" sign[0]. Given that the ones with the red circle but without the red slash typically mean up to what is shown is allowed and anything above is not (e.g. maximum speed, maximum width, maximum height), the one showing a car and a motorbike could reasonably be interpreted as anything up to the size of a motorbike and car are allowed but anything bigger (such as a lorry and a bus) are not. Adding a simple slash, as the rest of the world seems to do, and as per other prohibition signs in the UK and Europe (e.g. no right turn) would remove all ambiguity. Wonder if there's some strange history behind that apparent anomaly.
> that the ones with the red circle but without the red slash typically mean up to what is shown is allowed and anything above is not (e.g. maximum speed, maximum width, maximum height)
These number are limits on a continuous domain, where inclusion or exclusion of the limit number itself is basically meaningless. The list of vehicles is a set (without necessarily a clear order) which has fundamentally different properties so it's not surprising the meaning is slightly different. You couldn't have a sign that forbids pedestrians and cars but allows motor vehicles otherwise.
The rules are simply that when a red on white sign displays anything other than a number (with or without a slash) it means this thing is forbidden. If it's a number it means a high limit.
Back in the days when the League of Nations was deciding all this, there was a road sign in the German Empire consisting of a red circle around a white background with a black arrow pointing straight ahead (and no slash). This did not mean it's forbidden to go straight ahead, it meant it's _mandatory_ to go straight ahead - the thing that later on was changed to the white-on-blue arrow. (examples: https://de.wikipedia.org/wiki/Bildtafel_der_Verkehrszeichen_... but the sign must be older than that).
If you want to be picky, the "you must" signs generally had a narrower red ring than the "you must not" ones, but even that rule is not always adhered to on the linked page.
I think the slash was added in some cases because there's an old German sign with a black arrow on a white background with a red ring, that means _you must go this way_ instead of _you must not go this way_ as we'd read it today. So the slash on all such signs (no left turn etc.) is to make it doubly clear this is a prohibition not an instruction.
Fun fact: the German Empire had an additional convention that if the symbol (e.g. a motor car) was shown in outline instead of filled in, then the prohibition only applied on Sundays.
EDIT: looking at https://commons.m.wikimedia.org/wiki/Category:Diagrams_of_hi..., the 1927 German sign for "parking _allowed_" was a black P on a white background with a red circle; the prohibition sign contained the text "Parken verboten" (parking forbidden). So I can see why the German delegate might have objected to making the new "no parking" sign their old "yes you can park here" sign!
I always thought the slashed ones were ambiguous, as adding a slash on top of a red circle which already signifies prohibition could be interpreted as a double negation.
A very American article. To Europeans (and people in most other places) the answer is obvious that it comes from the street signs. The only open question is where their designers got the idea from.
I was rather bemused that the article takes a third of its length before getting to that point, and almost glances over the remaining question (apparently it comes from the subcommittee that designed the no parking and no stopping signs).
Being Australian, I accidentally rode my bicycle down the entry lane to a German autobahn after seeing a sign with a bike and a circle around it (not through it).
White (yellow in some countries) signs with a red circle are always prohibition signs (or speed/weight limits), no matter if there is a bar or not - actually only the "no stopping" and "no parking" signs have bars (two for no stopping). If something is allowed, the sign is white on blue.
That's an interesting example, as white arrow/arrows on blue in circle also exists, which limits (or otherwise indicates) the directions you can continue.
The one-way traffic sign does fit in, but most commonly you see it in situations where it's actually just informational, like the entrance of a road. In this case it doesn't limit you in any way, it's not like you have to enter that road. You will see a no entry sign on the other side of the intersection anyway, which does limit you. But it does inform you that you shouldn't expect oncoming traffic.
The horizontal one-way road sign is less common, and is often used in T-junctions. There it arguably does double duty.
It does mean that after entering that road you aren't allowed to turn around and go back, so there is a bit of a mandatory aspect there. Nevertheless I think it still fits best with the informational signs, also to separate it from the white arrow on a blue circle.
Well, not really. This sign is an indication that you will not encounter oncoming traffic.
The other end of the road will see a "No Entry" sign (red disc with a white horizontal bar) and any side street will get a "mandatory direction" sign (a blue disc with a with circle and a white arrow) that shows which direction is mandatory or a "no turning" sign showing which direction is prohibited. The square blue sign with an arrow is an indication that someone else has mandatory or prohibition signs.
For example here: https://maps.app.goo.gl/PwAYqUffz6uPLVZW6 you can see a "no right turn", a "one-way traffic" sign, and a "no entry" sign (all saying "except bikes"). The "one-way traffic" is definitely informative, it would be a disc otherwise.
it seems like it's less universal than I thought. Using just a rectangle with an arrow when coming from a side street rather than a circle makes no sense to me unless there are also no entry/no right turn/mandatory left turn signs as well.
I was very surprised to learn just how new this symbol is. I'm a bit too young for it but apparently there were times in my parents' lifetimes when few Americans would have understood it.
There was an HN discussion in 2020 about the oldest business or commercial establishment in various countries and/or continents. Many of those are involved with, variously, food service, alcohol, teaching, construction, or banking. In part because those are activities which have been with humans (or at least civilised, that is, inhabiting-cities humans) since the beginning, and have not been supplanted by some newer activity.
The Church requires that you've decided this needs to be organized, all you need to start praying before you go hunt for food is superstition.
The Princes Alice experiments show why superstition might be valuable (and so get preserved in a culture) if you don't have much technology to provide oversight. Children were told to perform a task and that an (invisible) Princess, Alice is watching to check they don't cheat while the adults are away. Superstitious children didn't cheat because they believed in Alice watching them. The non-superstitious children cheated, after first verifying that in fact Alice does not seem to exist (e.g. passing their hand through space supposedly occupied by the invisible princess)
That interpretation only works if you desperately want the comment containing the phrase "the church" to be wrong. If you insist on this unusual interpretation, then yes, farming isn't at least five times older than the church. But if you go with the usual interpretation of "the church" as a metonym for Christianity, as was very clearly intended by the implications of the statement, it is correct.
Why not go talk to some Muslims about the Islamic church? Or some Hindus about the church of Shiva? I'm sure you'll find the discussion edifying!
If you think about it, though, the symbol has been around longer than most people today have been alive, and for a substantial amount of the time people have been driving. Compared to other symbols, it may be fairly "new" (for example, the Christian cross or Islamic crescent), but in the realm of widely standardized symbols, it's pretty old.
Fine? They are all essentially the same, with different artistic style.
There can be regional differences on what signs are required. I only checked the Italian one, but that sign only prohibits cars, motorcycles are still allowed. If both are prohibited, they presumably display both signs, or prohibit all vehicles (including bicycles) with that sign.
A similarly recent symbol, from the late 1950s, is the peace sign. Designed by Gerald Holtom: https://en.wikipedia.org/wiki/Gerald_Holtom (wiki page for Mr Holtom includes a discussion of the peace symbol story)
Re. ubiquity making things hard to find— Recent application naming is infuriating! Consider, in GNOME, for example, Nautilus vs Files. "GNOME Files" does not, of course, help. Same with "Apple Photos".
GRRR!
About as helpful as trying to debug "An error has occurred".
Apple Photos, Music, Numbers, Notes… It’s truly exasperating trying to surface an answer for a question like “how do I sort photos in Apple Photos by date of photo not date added?”
At least Google figured out after the fact that golang made more sense than go.
and making "Apple Music" also refer to a subscription service is even worse.
you can only get away with so much by using "music.app" and "photos.app" - and it really doesn't apply on the phone. (Aside: how long until the iPhone is just the Apple Phone?)
I'd heard it referred to as a "bar sinister" before but when I looked it up I couldn't find anything to confirm that. I hadn't thought of looking it up in the context of heraldry.
I suppose dexter when it's left-to-right and sinister when it's right-to-left?
Yeah, which maybe makes it punnily appropriate that Ghostbusters has always used the "bend sinister" version given the theme of ghosts and the modern connotation of "sinister".
> March 1931, when the League of Nations, attempting to manage the sudden explosion in road traffic, convened a Convention Concerning the Unification of Road Signs in Geneva
It comes from traffic signs in the first half of the 20th century.
Sorry to be that guy, but I was less fascinated and more bemused by this one. Surely the origins of this would simply be somebody formalising the representation of “crossing something out”? An act as old as cave paintings, one assumes.
Can you find examples older than 100 years old that show a thing crossed out to mean "don't do this thing?" And how close are they to this representation? That's what the author was trying to find out.
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0: https://en.wikipedia.org/wiki/No_symbol
1: https://en.wikipedia.org/wiki/ISO_7010
2: https://www.compart.com/en/unicode/U+20E0
3: https://www.compart.com/en/unicode/U+1F6AB