The trick in the second line was suggested by James Clerk Maxwell. 
(See the first line of the final stanza.)
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monorhyme, n. and adj.
A poem or passage in which all the lines have the same rhyme; rhyming of this kind.

There was an old poet from Ronnet

Who was on a mission of moronit-

y; he set upon it

With bee in bonnet,

And begot a seventeen-syllabled sonnet.


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See also genethliacon, runcible.