Puzzle Lab
Try the problem first. Hints and full explanations are there when you want them.
The Blindfolded Cards
A clean invariant puzzle: split cards while blindfolded so both piles have the same number of face-up cards.
Prompt Injection Museum Guard
A tiny LLM security challenge: separate trusted instructions from hostile page text.
The Infinite Startup Payout
A probability puzzle about expected value, real-world constraints, and why math without context lies politely.
Tokenizer Trap
A small LLM puzzle about why models can write beautifully and still stumble on character counting.
The Parity Party Switches
A small parity puzzle where the trick is noticing what can never change, even when everyone is busy flipping switches.