graph LR D0["Day 0: Encode"]:::encode -->|"1 day"| D1["Day 1: Review 1"]:::success D1 -->|"2 days -- 2x"| D3["Day 3: Review 2"]:::success D3 -->|"4 days -- 2x"| D7["Day 7: Review 3"]:::success D7 -->|"7 days -- 2x"| D14["Day 14: Review 4"]:::success D14 -->|"16 days -- 2.1x"| D30["Day 30: Review 5"]:::success D30 -->|"30 days -- 2x"| D60["Day 60: Review 6"]:::success D1 -.->|"fail: reset to 1-day"| RESET["Day 2: Re-review"]:::fail subgraph Leitner["Leitner Box Comparison"] L1["Box 1: every 1 day"]:::leitner L2["Box 2: every 2 days"]:::leitner L3["Box 3: every 4 days"]:::leitner L4["Box 4: every 8 days"]:::leitner L5["Box 5: every 16 days"]:::leitner L1 -->|"promote on success"| L2 L2 -->|"promote on success"| L3 L3 -->|"promote on success"| L4 L4 -->|"promote on success"| L5 end classDef encode fill:#08519C,stroke:#041733,color:#fff classDef success fill:#4A90D9,stroke:#2C5F8A,color:#fff classDef fail fill:#E8795A,stroke:#C0392B,color:#fff,stroke-dasharray: 5 5 classDef leitner fill:#6BAED6,stroke:#3182BD,color:#fff