Pack 4 Quantifier quarry

Quantifier quarry is about counting. * means zero or more, + one or more, and ? makes the thing before it optional. Braces set exact limits: {3} is exactly three, {4,6} four to six. Put a quantifier after a group and the whole group repeats.

The first board catches three or more o’s in a row, so wooo is caught and look is spared. After that come hex colours like #fff and #9abc43, PINs of four to six digits, knock patterns like kkk-kk-k, and UK sort codes like 12-34-56. Par is tight on every level, so a well-placed count usually beats spelling things out.

Every level also has hidden checks: words you don’t see. Passing the words on screen solves a level; passing the hidden checks too ranks it.

Counting is what makes real formats possible, so Real-world formats is a good next step. The Quantifiers track also explains greedy and lazy matching.