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Creative Challenges

L3PRO· 100 lessons

10 unique formats nobody else teaches

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100 lessons across 10 themed modules: Code Detective (broken-codebase mysteries), AI Pair-Reversed (catch Claude's deliberate bugs), Time-Travel Refactor (Python 2.4 → modern), Bug Bounty, Code Golf (shortest wins), Refactor Master (legacy → idiomatic), Whodunit Mysteries, Performance Showdowns, Edge Case Hunter, Magic Demystified (dunders, descriptors, metaclasses, full mini-ORM).

📋 WHAT YOU'LL LEARN

🕵️ Case 01: The Off-By-One Killer · 🕵️ Case 02: The Mutable Default Argument · 🕵️ Case 03: The Floating-Point Money Heist · 🕵️ Case 04: The Integer Division Trap · 🕵️ Case 05: The Shadowed Built-in · 🕵️ Case 06: The Closure Conspiracy · +9 more

1
🕵️ Case 01: The Off-By-One Killer
fixFREE
→
2
🕵️ Case 02: The Mutable Default Argument
fix125 XP🔒 PRO
→
3
🕵️ Case 03: The Floating-Point Money Heist
fix125 XP🔒 PRO
→
4
🕵️ Case 04: The Integer Division Trap
fix125 XP🔒 PRO
→
5
🕵️ Case 05: The Shadowed Built-in
fix125 XP🔒 PRO
→
6
🕵️ Case 06: The Closure Conspiracy
fix125 XP🔒 PRO
→
7
🕵️ Case 07: The Encoding Mystery
fix125 XP🔒 PRO
→
8
🕵️ Case 08: The Dict Mutation Heist
fix125 XP🔒 PRO
→
9
🕵️ Case 09: The Silent Exception Swallower
fix125 XP🔒 PRO
→
10
🏆 Case 10 — Capstone: The Race-Condition Counter
mission200 XP🔒 PRO
→
11
🤖 Spot Claude's mistake: flatten a nested list
fix125 XP🔒 PRO
→
12
🤖 Spot Claude's mistake: email validator is too permissive
fix125 XP🔒 PRO
→
13
🤖 Spot Claude's mistake: pagination off-by-one
fix125 XP🔒 PRO
→
14
🤖 Spot Claude's mistake: dedup lost the order
fix125 XP🔒 PRO
→
15
🤖 Spot Claude's mistake: Fibonacci that never finishes
fix125 XP🔒 PRO
→

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