Single-File “20 Questions” Differential Guesser

Educational toy app: answers are stored only in the #hash so you can copy/paste the URL to reproduce the round. Not medical advice and not a diagnostic device. If you’re worried about symptoms, contact a licensed clinician or local emergency services.
Next question
Chosen to eliminate diagnoses quickly (approx. expected remaining)
— remaining
— eliminated
— answered
History
All questions/answers remain visible during this round
Remaining diagnoses
Shown for transparency (not a real diagnosis)
—
Tips:
  • Restart clears only this round (and the hash).
  • Back/forward works because the hash is the state.
  • Some questions may not help if many diagnoses are compatible with “any” answer.
About the model
Lightweight rule-based elimination
How it works: each diagnosis lists which answers are compatible with certain questions. If a diagnosis does not specify a question, it is treated as compatible with any answer (so it won’t be eliminated by that question). The app picks the next question with the smallest estimated expected remaining set.
This is intentionally simplified. Real clinical reasoning depends on timing, severity, exam findings, labs, imaging, prevalence, and risk.