Created: 2012-03-23 23:22
Updated: 2018-11-21 01:04
License: mit

On the structure of a limerick

Limericks have a fairly loose form. The rhyme scheme and syllable count is typically something like this:

A (7, 8 or 9 syllables)
A (7, 8 or 9)
B (5 or 6)
B (5 or 6)
A (7, 8 or 9)

And as if that weren't loosey-goosey enough, they can have either anapaestic meter (duh-duh-DUM, duh-duh-DUM) or amphibrachic meter (duh-DUM-duh, duh-DUM-duh)!

So, I chose the following as the canonical example to work from when building this limerick detector:

There was a young student from Crew
Who learned how to count in base two.
His sums were all done
With zero and one,
And he found it much simpler to do.

Going by the canonical example above, Nantucket is set to look for limericks with the following structure:

A (8)
A (8)
B (5)
B (5)
A (9)

And eventually will perhaps look for the following meter as well:

duh DUM duh duh DUM duh duh DUM
duh DUM duh duh DUM duh duh DUM
duh DUM duh duh DUM
duh DUM duh duh DUM
duh duh DUM duh duh DUM duh duh DUM

Example results

from Swann's Way by Proust:

bad conduct should deserve Was I
then not yet aware that what I
felt myself for her
depended neither
upon her actions nor upon my

was wonderful to another
How I should have loved to We were
unfortunate to
a third Yes if you
like I must just keep in the line for

to abandon the habit of
lying Even from the point of
view of coquetry
pure and simple he
had told her can't you see how much of

from Ulysses by James Joyce:

grace about you I can give you
a rare old wine that'll send you
skipping to hell and
back Sign a will and
leave us any coin you have If you

then he tipped me just in passing
but I never thought hed write making
an appointment I
had it inside my
petticoat bodice all day reading

meant till he put his tongue in my
mouth his mouth was sweetlike young I
put my knee up to
him a few times to
learn the way what did I tell him I

from Genesis:

in the iniquity of the
city And while he lingered the
men laid hold upon
his hand and upon
the hand of his wife and upon the

Amorite and the Girgasite
And the Hivite and the Arkite
and the Sinite And
the Arvadite and
the Zemarite and the Hamathite

from Huckleberry Finn by Mark Twain:

he suspicion what we're up to
Maybe he won't But we got to
have it anyway
Come along So they
got out and went in The door slammed to

and see her setting there by her
candle in the window with her
eyes towards the road and
the tears in them and
I wished I could do something for her

from The Brothers Karamazov by Fyodor Dostoevsky:

eyes with a needle I love you
I love only you Ill love you
in Siberia
Why Siberia
Never mind Siberia if you

are children of twelve years old who
have a longing to set fire to
something and they do
set things on fire too
Its a sort of disease Thats not true

and be horror struck How can I
endure this mercy How can I
endure so much love
Am I worthy of
it Thats what he will exclaim Oh I

TODO (maybe)

take meter into account
maybe make it worth with different limerick formats qua different strategies one can choose make the search algorithm faster/more efficient (perhaps by not starting from scratch for each go-round)

How to use

Written with Python 2.7.2, using the awesome nltk library and the CMU pronunciation dictionary.

pip install numpy  
pip install nltk  

To get the CMU dictionary (which is critical):

$ python  
>>> import nltk  
NLTK Downloader
    d) Download   l) List    u) Update   c) Config   h) Help   q) Quit
Downloader> d

Download which package (l=list; x=cancel)?
  Identifier> cmudict
    Downloading package 'cmudict' to ~/nltk_data...
      Unzipping corpora/

To add my CMU-based suffix dictionary, just stick 'cmusuffdict' into a new directory 'cmusuffdict' in your nltk_data/corpora/ directory.

$ mkdir ~/nltk_data/corpora/cmusuffdict
$ mv suffdict_creation/cmusuffdict ~/nltk_data/corpora/cmusuffdict/

Once you have all that, you can search for accidental limericks in any text (from a directory containing both Nantucket's files and the text) on the command line with:

$ python --text <filename>


$ python --text ulysses.txt

Or, if you don't yet have the text of Ulysses lying around:

$ wget -O ulysses.txt
$ python --text ulysses.txt

If you're curious about how I handled rhyming words not in the CMU dictionary, check out and I get approximately 90.85% accuracy, according to my tests. Or you can read my ridiculously long blog post about the making of Nantucket -

Also, I finally webbified Nantucket so it can also be used as a cgi script (imported cgi, added the shebang, chmod a+x, and refactored it to allow for the option of handling urls rather than just files and using html formatting when needed), so you can just play with Nantucket by pointing it at links to text files on the web here:

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