Welcome to competitive slow-gaming.
Enable GPS and roam the Earth. Grid Walking will mark squares visited automatically. Visit 3 squares, get the 4th free and upgrade to a larger square. How large a square can you get?
Visit bonus areas to get bonus points you can use to long-press-select the impossible-to-reach squares and mark them visited. Choose wisely, though, as bonus points are a scarce resource!
Grid Walking uses the OpenStreetMap-Tool "osmdroid" for maps. Osmdroid is released under the Apache 2.0 license, and is used unmodified.
Grid Walking requires these permissions:
- "Location" for knowing your location
- "Networking" to download map tiles