From Henry Beard's Poetry for Cats:

Cleaning the Box

by Alfred, Lord Tennyson's Cat

Cat-turds on parquet blocks
Are one clear sign for thee!
'Tis time to do the cleaning of the box
Which you put out for me.

For while to you my litter seems pristine,
To me it plainly reeks,
Like stinking bilges in some barkentine,
Becalmed for weeks.

Twilight and evening bell
And after that the dark!
And there shall be no inkling of farewell,
When I embark.

And though you call for me with plaintive cries
That echo from the rocks,
You will not see your cat materialize,
'Til you have cleaned my box.