The doctrine of sin as a mastery ladder — the origin of evil and the angelic fall, the historicity of Adam, original sin and imputation, total depravity and the noetic effects, inability and responsibility, sin as act and state, the classifications and aggravations, the unpardonable sin and the warning passages, and the wages of sin that drive us to the Savior. Each mode trains a different skill; the final exam ranges over the whole course. Unlock each subtopic by scoring at least 90% on its mastery check. Cards you grade enter spaced review: the dashboard tells you when they fall due.