How the em dash became the tell for AI writing.

Named for its width, about the size of a capital M. For three hundred years it was the writer's tool for the interruption, the aside, the breath before the turn. Laurence Sterne filled Tristram Shandy with them. Emily Dickinson built whole poems on them.

Then the machines learned to write, and they liked it more than anyone ever had. By 2024 people were calling it the tell: the mark that gives away a paragraph nobody typed. Writers started deleting their own. Some added a line to every prompt.

That line is on this shirt. It does not explain itself.