Core · Drill
The core quiz loop of Drill. Randomized question order, a spaced-repetition scheduler that resurfaces missed questions more often, and localStorage persistence so progress resumes cleanly across devices. No backend — everything runs client-side in a single HTML file.
The scheduler uses a simplified SM-2 algorithm: each question's interval is adjusted by performance, and the next-due question is selected by lowest interval. Lean enough to fit alongside the FRQ engine and the deck loader in one self-contained file.