A theorem is a general proposition that is not self-evident which is to be proved by a chain of reasoning; a statement that is demonstrably true by argument.
"Thomas Jefferson derived ‘all men are created equal’ from Checkers" is a simple enough general proposition. And clearly not a statement that is self-evident.
It's more like an off-the-wall bizarre notion. A curiously odd statement by any reasonable measure.
And yet, it's easy to show that the proposition could possibly be true in a number of different ways. With that demonstrable fact in itself being something consistent with a provably true theorem.
What we in America now call Checkers was called Draughts or Drafts back in Revolutionary days. The game pieces then and now called 'men'. Those men having no kings among them at game's start. With the rules governing their moves from the outset creating a set of equal men existing on a checkerboard.
That's the easy part. Showing the proposition does qualify as a theorem, and that the Checker Theorem is possibly true.
Then as the investigation into the Checker Theorem goes deeper and deeper things continue to get curioser and curioser.
