Privacy policy
Last updated 2026-11-06.
This site is designed to collect as little as possible.
In short
- No accounts, no sign-up, no comments, no newsletters, no advertising and no affiliate links.
- The site sets no cookies of its own. Your theme choice is remembered in your browser’s local storage, which never leaves your device.
- Every figure runs entirely in your browser. Nothing you do in a figure is sent anywhere. Your approximate starting position on the home page is guessed from your browser’s time-zone setting, on your device; no location permission is requested.
- We do not sell or share personal data.
Analytics
We use Google Analytics 4 to count visits and see which pages and figures are used, so we know what to improve. Google Analytics sets first-party cookies and receives your IP address, which Google uses to estimate an approximate location; Google Signals and ad-personalization are switched off for this site. You can opt out with the Google Analytics opt-out browser add-on or by blocking cookies. Google’s practices are described at How Google uses information from sites that use its services.
Hosting
The site is static and served by Cloudflare. Like any web host, Cloudflare processes standard request data (such as IP addresses) to deliver pages and protect the service; see Cloudflare’s privacy policy.
If you write to [email protected], your message is used only to reply and is not added to any list.
Your rights
Depending on where you live (for example under the GDPR or the CCPA), you may have rights to access, correct or delete personal data. Because we hold essentially none, the simplest route is to email us and we will help.