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 [email protected] — 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.