A Tale of Two Qubits: How Quantum Computers Work
arstechnica.com"If the phonebook has 10,000 entries, on average you'll need to look through about half of them—5,000 entries—before you get lucky."
How could one possibly search a phone book so poorly? Even a dumb binary search would eliminate about half the remaining entries each time, getting the job done after only checking around 15 entries.