Duality jokes

Roses are red.

Violets are blue.

I have schizophrenia,

And so do I.

The twin towers are like genders, there used to be two of them.

What do the Twin Towers and gender have in common? There used to be two of them, but now it's a sensitive topic.

What do the Twin Towers and genders have in common? There used to be two of them, but now it's a sensitive subject.

Genders are like the Twin Towers.

There used to be 2 of them, but now it’s a sensitive subject.

Parallel lines have so much in common, it’s a shame they’ll never meet.