Pattern Hunter

Craft a single regex that catches all the green words, skips all the red ones, then shrink it under par.

How to play

You get two word lists: must-match (green) and must-not-match (red). Type one regular expression that matches every green word and none of the reds. The words light up live as you type. Once it separates them, shorten your pattern to beat the par length.

• Your pattern is tested against each word; add anchors yourself if you need them
• Match all greens, reject all reds, then golf the length down
• Score rewards a short pattern that comes in under par

Controls

• Desktop: type your pattern in the input and press Enter or Submit; Reveal shows an example solution
• Phone & tablet: tap the input and type with the on-screen keyboard

Game modes

• Difficulty: Easy, Medium or Hard word sets
• Daily for a shared puzzle, Practice for an endless stream

Tips & strategy

• Hunt for a substring or character class the greens share and the reds lack — often two or three characters is enough
• Reveal gives a working example; treat its length as the target to undercut

What you'll learn

Pattern Hunter is regex golf — a code-golf puzzle about expressive, minimal pattern matching.

• Skills: regular expressions, pattern matching, concise problem-solving
• Best for: roughly grades 9–12 (ages 14+)
• For parents & teachers: concise, expressive pattern matching.

About Pattern Hunter

Pattern Hunter is regex golf: a code-golf puzzle about expressive, minimal pattern matching. It is an original, free browser game built in-house for PlayPendium.

A free, original browser game on PlayPendium — no download, no install. Browse all games →