A Paradox, a Paradox, a Most Ingenious Paradox!

KING:
For some ridiculous reason, to which, however, I've no desire to be disloyal, some person in authority, I don't know who, very likely the Astronomer Royal, has decided that, although for such a beastly month as February, twenty-eight days as a rule are plenty, One year in every four his days shall be reckoned as nine and twenty. Through some singular coincidence, I shouldn't be surprised if it were owing to the agency of an ill-natured fairy, You are the victim of this clumsy arrangement, having been born in leap-year on the twenty-ninth of February; And so, by a simple arithmetical process, you'll easily discover, That though you've lived twenty-one year, yet, if we go by birthdays, you're only five and a little bit over!

RUTH AND KING:
Ha! Ha! Ha! Ha!
Ho! Ho! Ho! Ho!

FRED:
Dear me!
Let's see! (counting on fingers)
Yes, yes; with yours my figures do agree!

ALL:
Ha! Ha! Ha! Ho! Ho! Ho! Ho!

FRED:
How quaint the ways of Paradox!
At common sense she gaily mocks!
Though counting in the usual way,
years twenty-one I've been alive,
Yet, reckoning by my natal day,
I am a little boy of five!

-Gilbert and Sullivan's Pirates of Penzance
Parce que I had this song stuck in my head all day this February 29th