Rule Lab prototype by rnn.ai

• Click a number to test it. Green means the hidden rule accepts it; red means it doesn't. Each test spends one from your budget.
• The list below holds every candidate rule — exactly one is the real one, and no two behave identically on 1–30.
• Select a rule and commit. You can commit early, but you only get one shot.
• The assist crosses out hypotheses your evidence has already refuted. Turn it off to do the elimination yourself.

What it teaches: the scientific method. A hypothesis is never proven by agreeing examples, only refuted by one counterexample — so the best test is a number the surviving rules disagree about.