[Arkle]

To convey one's mood
In seventeen syllables
Is very diffic.

[dighton]

Regarding #27:

Finally, he fixed each picture
With a saturate solution
Which was made of hyposulphite
Which, again, was made of soda.
(Very difficult the name is
For a metre like the present
But periphrasis has done it.)

-- Lewis Carroll, Hiawatha's Photographing.

[ru4liberty]

To convey one's mood
In seventeen syllables
Is very diffic.

Now that's funny!