Too bad Piotr Wozniak (inventor of SuperMemo) is such a hermit and uncompromising of his lifestyle choices, that most of his life's work was eventually superseded by open-source solutions (Anki + FSRS).
I had tons of material in SuperMemo for years. Gave up and fully switched to Anki.
At least I'm thankful for his spaced-repetition algorithms. Also, his articles restored my love for learning and helped me confirm that school was an insane waste of time and resources.
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