Last updated 2 November 2026

Privacy

The short version: there are no accounts and no ads, and your progress stays on your device. derived counts visits and how each puzzle is played with its own analytics, anonymously unless you allow a cookie. Nothing is shared with advertisers. The only third-party script is Google reCAPTCHA on the contact form, once you start writing a message.

What's stored on your device

derived uses your browser's local storage to remember a few things between visits. This data never leaves your device and is never sent to us.

• Your progress and solve times for each day's puzzles, used for your results and streaks.
• Which games you've already seen the rules for.
• Whether you've turned sounds off.
• Whether you prefer light or dark mode.
• Whether you've chosen to hide the timer.
• Which welcome and news messages you've closed.
• Whether you accepted or rejected the analytics cookie, so you're only asked once.

This storage is only used to provide the game you're playing, so it doesn't need your consent. You can delete it at any time by clearing this site's data in your browser settings. Doing so resets your progress and streaks.

Analytics

derived uses its own analytics, not Google Analytics or any other company's. Each time you open a page, it records the page, the website that sent you here, your screen size, language and time zone, roughly how long the page was open, and clicks on links to other sites. It also adds your country and your browser, operating system and device type, worked out from your connection. Your IP address isn't stored.

Without a cookie (before you choose, or if you reject it), nothing is stored on your device. To count daily visitors, your IP address and browser are combined with a secret that changes every day and turned into a code that can't be reversed. Tomorrow you get a different code, so visits can't be linked across days.

If you accept the cookie, two first-party cookies are set: a random visitor ID, kept for 13 months, and a random session ID, kept for 30 minutes after your last visit. They let derived see return visits and how people move between pages, and they're attached to your puzzle records too. They aren't linked to your name or anything else about you, and are never shared.

You can change your mind any time with the Cookies link at the bottom of every page. Rejecting deletes both cookies straight away.

Gameplay statistics

When you play, the site also sends small records of how each puzzle went, so we can see how hard each game is and where people get stuck. They include:

• Which game and day, its difficulty, and whether you started, solved or left the puzzle.
• How long you took, how many moves and undos you made, and when you used a hint, made a mistake or opened the rules.
• Rough context: phone, tablet or desktop, mouse, touch or keyboard, the hour of day, your country, and your sound, theme and motion settings.
• Your current streak for that game and how many days you've played.
• When you share a result, change the sound, theme or timer setting, or close a message.

Records contain no name or account. They only carry the cookie IDs above if you accepted the cookie. Your country is worked out from your connection and only the country is kept.

Contact form

If you send a message through the contact page, it's emailed to the developer along with your name if you gave one and the country your connection comes from. It isn't used for anything else, isn't shared, and isn't added to any mailing list. Don't include anything in a message you'd rather keep private.

To keep spam out, the form uses Google reCAPTCHA. It only loads once you start writing a message, so just visiting the contact page loads nothing from Google. Once loaded, Google may set cookies and collect information about your device and how you use the page, under Google's Privacy Policy and Terms of Service. No other page uses it.

Hosting

Like any website, our hosting provider may briefly process standard technical details of each request, such as your IP address and browser type, to deliver the site and keep it secure.

Support link

The "Buy me a coffee" link opens Ko-fi, a separate website with its own privacy policy. Nothing is shared with Ko-fi unless you choose to support there, and derived never sees your payment details.

Changes

If derived ever collects anything beyond what's described here, this page will be updated first, and you'll be asked for consent wherever the law requires it.

Questions? Get in touch.