About Hoot & Fox

A cosy binary logic puzzle, made independently in the UK.

What is Hoot & Fox?

Hoot & Fox is a Binairo puzzle (also called Takuzu, and the puzzle behind LinkedIn's Tango) played with owls and foxes. The iPhone app was released on the App Store on 20 September 2026; this site has a free Daily, unlimited puzzles and a guide to every solving technique.

How are the puzzles made?

The Daily and Unlimited puzzles on this site come from the Hoot & Fox puzzle engine, the same one that powers the app. It starts from a complete, valid grid and removes givens one at a time. A removal is kept only if the puzzle still has exactly one solution and a solver that uses nothing but the seven human techniques in the techniques guide can still finish it. That's why no Hoot & Fox puzzle ever needs a guess.

Each puzzle is then graded into one of six tiers by the hardest technique it may need: tier 1 uses only bookends, gap fill and counting; tier 2 adds count pressure; tiers 3–4 add look-ahead; and tiers 5–6 add chain reasoning. The Daily is built from the date, so everyone gets the same grid, in the browser and in the app.

Get in touch

Email hello@hootandfox.com — bug reports, puzzle questions and accessibility feedback all welcome. Journalists can grab the press kit.

Hoot & Fox is not affiliated with LinkedIn. Tango is a LinkedIn Games title.