New Years party themes

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Today's xkcd:

The mouseover title: ""Off-by-one errors" isn't the easiest theme to build a party around, but I've seen worse."

The Wikipedia entry tells us that

A fencepost error (occasionally called a telegraph pole, lamp-post, or picket fence error) is a specific type of off-by-one error. An early description of this error appears in the works of Vitruvius.

with a link to

Moniot, Robert K., Who first described the "fence-post error?", Fordham University, retrieved 2016-07-07.

Unfortunately the link is dead, and a search for the title turns up no other URL. But a few minutes on the Perseus site finds the Vitruvian source — De Architectura, Book III, Chapter IV, Section 3. In the English translation from Morris Hicky Morgan's edition:

The columns are then to be distributed over the stylobates in the manner above described: close together in the pycnostyle; in the systyle, diastyle, or eustyle, as they are described and arranged above. In araeostyle temples one is free to arrange them as far apart as one likes. Still, in peripterals, the columns should be so placed that there are twice as many intercolumniations on the sides as there are in front; for thus the length of the work will be twice its breadth. Those who make the number of columns double, seem to be in error, because then the length seems to be one intercolumniation longer than it ought to be.

Or in the Latin original:

Supra stylobatas columnae disponendae, quemadmodum supra scriptum est, sive in pycnostylo, quemadmodum pycnostyla, sive systylo aut diastylo aut eustylo, quemadmodum supra scripta sunt et constituta. in araeostylis enim libertas est quantum cuique libet constituendi. sed ita columnae in peripteris conlocentur, uti, quot intercolumnia sunt in fronte, totidem bis intercolumnia fiant in lateribus; ita enim erit duplex longitudo operis ad latitudinem. namque qui columnarum duplicationes fecerunt, erravisse videntur, quod unum intercolumnium in longitudine plus quam oporteat procurrere videtur.

So the off-by-one themed New Year's Eve party could be decorated with temple floor plans, with appropriate Vitruvian quotations. Unfortunately I don't think there's any off-by-one resonance in Leonardo's Vitruvian Man. But the party could also feature a ceremonial reading of Edsger Dijkstra's "Why numbering should start at zero".

I was surprised to find that Google Scholar gives only 825 hits for {"off by one error"}, which supports Randall Munroe's suggestion that it "isn't the easiest theme to build a party around", even in a geeky subculture.

Update — Philip Taylor found the Moniot Vitruvius piece on the Internet Archive, where I should have thought to look.



  1. Francisco said,

    December 30, 2019 @ 2:19 pm

    Leonardo's diagram being too elemental, may I suggest Le Corbusier's take on Vitruvius man, the Modulor (e.g. In name and complexity it promises a surfeit of left-over quasi-integers.

  2. peterv said,

    December 30, 2019 @ 4:42 pm

    It is often said that the two hardest problems in computer science are 1) cache invalidation 2) naming and 3) off-by-one errors.

  3. Peter Taylor said,

    December 30, 2019 @ 4:55 pm

    I'm more familiar with the variant "out-by-one error", but that has only 10 hits on Google Scholar.

  4. Robert Coren said,

    December 31, 2019 @ 10:47 am

    My problem with this is that the kind of "off-by-one error" the cartoon refers to isn't a fence-post error; it's subtracting the birth year from the current year and still getting the age wrong because you don't know whether the person was born before or after the current date.

  5. Andrew Usher said,

    January 1, 2020 @ 1:02 pm

    Correct, but I think that's part of the joke.

    I'm certainly familiar with the concept of the fencepost/off-by-one error, but don't normally associate a specific term with it. When you have to explain to someone that's made that error, after all, giving it a name doesn't help.

    Vitruvius certainly describes it almost canonically: I note, though, that the English translation is overly literal in repeating 'seem' – we would say the length islonger, not that it seems to be. This type of translation error (and it truly ought to be considered one) really annoys me because it's still seen all the time, even though we should know better.

    k_over_hbarc at

  6. Andrew Usher said,

    January 10, 2020 @ 6:10 pm

    Note I messed up the closing italic tag. That's one reason for not using them more often, and why I really wish for an edit-posts feature or at least a preview so that those errors that are much more obvious in the displayed message than in the source text might be caught.

  7. Leo said,

    January 11, 2020 @ 2:08 am

    On more pedantic lines, I note the lack of an apostrophe in New Years party. Is that a typo for possessive New Year's party, or is the apostrophe-free New Years serving as a modifier of party?

    In UK English the start of January is New Year, but US English seems to favour New Years, making the modifier interpretation more likely. There even seems to be a difference in intonation: UK, Happy New Year; US, Happy New Years.

  8. Andrew Usher said,

    January 11, 2020 @ 10:05 am

    No, always "Happy New Year", no -s. There is a difference in stress, though.

    I don't know where you got 'New Years party' but I would expect the apostrophe to be kept there. 'New Years' without it is never standard, as far as I know.

  9. Leo said,

    January 11, 2020 @ 10:22 am

    @Andrew Usher: "New Years party" is in the LL post title.

    Maybe I misheard "New Years", or over-generalised from a single example.

  10. Andrew Usher said,

    January 11, 2020 @ 4:57 pm

    Well, I suppose I should have noticed that. I can't speak to how it happened, but now that you've pointed it out it certainly does look wrong. I'd be less surprised to see New Years' with a misplaced apostrophe than New Years with none at all.

    I don't know – maybe there are people that would say "Happy New Year's" – given that the holiday is generally called (in the US) New Year's , it is a natural enough developement. It would be 'New Year' for me, though, and that's the only form I can ever remember hearing.

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