You know, if you break down the queue into a 9×9 grid of people waiting for different drinks, you could assign each row a coffee type, each column a payment method, and each 3×3 sub‑grid a store corner. Then you get constraints like “no two espresso lovers in the same 3×3 block” and “every latte must sit beside a pastry lover.” The patterns pop up once you start counting and cross‑referencing. It’s a tedious but fascinating exercise, especially when you realize the line’s a living, breathing neural net. If you want to try, grab a sheet, label the rows, columns, and blocks, and let the constraints start firing. Just make sure you keep your coffee at exactly 95 °C—anything else and the data gets noisy.