Topsyturveydom

Like many of Gilbert's plays, Topsyturveydom is based on one of
Gilbert's Bab Ballads, quoted below.

The other night, from cares exempt,
I slept—and what d'you think I dreamt?
I dreamt that somehow I had come
To dwell in Topsy-Turveydom!—

Where vice is virtue—virtue, vice:
Where nice is nasty—nasty, nice:
Where right is wrong and wrong is right—
Where white is black and black is white.