Haystack — Build, Play & Share Bulls & Cows

How it works

Pick a difficulty, generate a unique-solution puzzle (a set of Bulls & Cows clues), then play it right here. Share the puzzle link with friends, or reveal the answer if you’re teaching or stuck.

Easy: 4-digit code, 5 clues
Medium: 6-digit code, 7 clues
Hard: 7-digit code, 7 clues (large search space; now verified against full space)

Step 1 — Choose & Generate

Difficulty:

Pick a difficulty and click Generate.

Clues

#	Guess	Bulls	Cows
No clues yet.

Your Attempts

#	Guess	Bulls	Cows
No attempts yet.

Step 2 — Play

After generating or opening a shared link, the clues appear below. Make guesses until you get all Bulls.

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