- [x] Tutorial World #LEAN ⏳ 2025-02-17 📅 2025-02-21 ✅ 2025-02-24
 - [<] Addition World #LEAN 🔽 📅 2025-03-22
 - [ ] Implication World #LEAN 🔽 📅 2025-03-22
 - [ ] Multiplication World #LEAN 🔽 📅 2025-03-22
 - [ ] Schedule further worlds #LEAN 🔽 📅 2025-03-22