Privacy Policy

Effective date: October 18, 2026 · Updated November 1, 2026 (this website)

This policy explains how Many Hands (the "App") handles information on iPhone (App Store) and on Android (Google Play), and how this website handles it. You never create an account, and we never ask for your name, email address or phone number. Many Hands is a shared game: the squares you solve are printed on a mural that every player sees, with your seal (a small pink stamp generated for you, with no name or text in it).

Your device ID and our game server

The first time you open the App, it generates a random device ID on your device. It is not derived from your phone's hardware, your advertising ID or your Apple or Google account, and it is stored only in the App's data. The App sends it to our game server with every request, for example when you take a square or submit one, so the server knows which square is yours.

Our game server runs on Cloudflare (Workers, Durable Objects and D1 databases; painting images are served from Cloudflare R2). For each device ID it stores:

• the squares you took and solved on each mural, the cells you submitted, when you solved them, how many wrong submits a square received, and the seal shown on your squares;
• your counts: squares painted ("hands"), daily streak and the last day you played, and which murals you contributed to;
• if you allow notifications, a push token (see below).

Other players see your seal on the squares you painted and the number of hands on each mural, never a name or your device ID. Like any web service, Cloudflare processes your IP address to deliver requests and protect the service from abuse; we do not store it with your game data. If you delete the App, the device ID is lost and the App starts with a new one.

Other information the App collects

• Play data: events such as squares taken, solved and left, wrong submits, rows borrowed, lessons played, streaks and session length, through Google Firebase Analytics, to tune the puzzles and improve the game.
• Device and diagnostic data: device model, operating system version, language, app version, crash reports and performance data (Firebase Analytics and Crashlytics).
• Game settings: the App downloads rules and settings from Firebase Remote Config.
• Advertising identifier: on iPhone, the IDFA, only if you allow tracking in Apple's App Tracking Transparency prompt; on Android, the Google advertising ID, which you can reset or delete in your device settings. Ad partners use it to show and measure ads, and in the EEA, UK and Switzerland only for personalised ads if you consent (see below).
• Approximate location: advertising partners may infer a coarse location such as country or city from your IP address. The App never uses GPS location.
• Purchases: Apple or Google Play processes every payment. We only learn that a purchase such as "Remove ads" happened.

Notifications: "your mural is complete"

After your first square is printed, the App may ask whether you want a note when a mural you helped paint is complete. Only if you allow it, the App gets a push token from Apple's push notification service (iPhone) or Firebase Cloud Messaging (Android) and sends it to our server with your device ID. We use Firebase Cloud Messaging to deliver these notifications. Turn them off any time in your device settings.

Ads and consent (EEA, UK, Switzerland)

The App shows ads through Unity LevelPlay and Unity Ads: a full-screen ad now and then when you leave a finished square, and a rewarded ad only when you choose to "borrow a hand". There are no banner ads. Players in the European Economic Area, the United Kingdom and Switzerland see the App's own consent question before any ad is loaded:

• Accept and Decline are equal choices. If you decline you still see ads, but they are not personalised, and on iPhone the App does not show the App Tracking Transparency prompt.
• To know whether to ask, the App checks on your device the store country, the SIM or mobile network country, your time zone and your region setting. These checks stay on the device.
• Your choice is saved on the device and passed to Unity LevelPlay. Our play statistics record whether the question applied and what you chose.
• Change your choice any time: Settings › Privacy choices.

On iPhone outside these regions, or after you accept, the App may show Apple's App Tracking Transparency prompt; you can allow or deny tracking there.

Sharing

When you tap Share, the App draws an image of the mural with your squares on your device and hands it, with a short text and a link to the mural's public page, to the system share sheet. You choose where it goes; we do not receive the image. The link marks the squares you painted on that mural, without your name or device ID. On iPhone, saving the image to Photos asks for permission to add it. The App does not read your photos and does not use your camera, microphone or contacts.

Game Center and Google Play Games

Leaderboards and achievements use Apple Game Center on iPhone and Google Play Games on Android. If you are signed in, Apple or Google shares your player name and scores so you can appear on leaderboards. There is no chat and no player-to-player messaging in the App.

The paintings

Murals are made from public-domain (CC0) images from the open-access collections of The Met, the Art Institute of Chicago, the Cleveland Museum of Art, the Rijksmuseum and the National Gallery of Art. Every pixel on a mural comes from a puzzle solution; players cannot draw or upload anything.

How we use information

• To run the shared mural: hand out squares, check submits, print squares with your seal, keep streaks and counts.
• To send the notifications you asked for.
• To understand how squares and lessons are played and make them better, and to diagnose crashes.
• To show ads that keep the App free, and to measure them.

We do not sell your personal information.

Service providers

These providers may process data on servers outside your country under their own policies and safeguards.

Your choices

• Ad consent (EEA, UK, Switzerland): Settings › Privacy choices in the App.
• Tracking (iPhone): the App Tracking Transparency prompt, or iOS Settings › Privacy & Security › Tracking.
• Advertising ID (Android): reset or delete it in your device settings.
• Notifications: turn them off in your device settings.
• Fewer ads: the one-time "Remove ads" purchase turns off the ads between squares.
• Offline play: the Sketchbook works without a connection; its squares stay on your device and are not sent to our server.

Keeping and deleting data

Progress, settings and the device ID stored on your device are removed when you delete the App. On our server, squares already printed stay part of the shared mural (with their seal) for as long as the mural is kept; counts, streaks and push tokens are kept while the App is in use. Firebase keeps play statistics and crash data for a limited time.

The App does not show your device ID, so to ask for access or deletion, email us at quang.app@gmail.com with roughly when you played and, if you can, the date of a mural you painted. We will delete the data associated with your device on request: the push token, your counts and streak, and the link between your device ID and your squares (the squares stay on the mural without it).

This website

This website (game-studio.quangmv.app/many-hands) has no accounts, no cookies and no ads. To count visits it uses Cloudflare Web Analytics, which sets no cookies, does not use local storage for tracking and does not fingerprint your browser; we only see totals such as page views, the referring site, country and device type, never who you are. It is served by Cloudflare, which processes your IP address and browser details to deliver the pages and protect the site, as any web host does. The home page shows today's mural and finished prints by reading public data from our game server; that request carries no identifier. The practice square on the Play page runs entirely in your browser: nothing you paint is sent anywhere and it is never added to the shared mural. To let you resume a square and keep a streak, the page stores your board, the days you solved and your times in your browser's local storage; clear your site data to remove them.

Children

The App is not directed at children under 13, and we do not knowingly collect personal information from children. If you believe a child has given us personal information, contact us and we will delete it.

Security and changes

Everything the App sends travels over encrypted HTTPS connections. If this policy changes, we will update the effective date above and announce important changes in the App or on this page.

Contact