Adaptive quiz that gets harder until you slip

You think you know a topic until someone actually tests you on it. This quizzes you, starting easy and getting harder until you get one wrong, then explains exactly what you missed in plain terms and keeps quizzing the same weak spot until you nail it. For revision that finds the gap instead of letting you re-read what you already know.

Quiz me on [topic]. Start easy, get harder until I get one wrong. When I miss, explain what I missed simply, then quiz me again on the same area until I get it right.