What are good ways to spray paint a QR code on a footpath? The QR would be of a URL. The QR should be big enough like 4 A4 size papers. I though of cutting out the white boxes from a printed paper and spray on it but what about white dot islands. The precision needs to be good enough for a cell phone camera to detect it on the floor from standing distance.
Here's a QR Code Stencil Generator which automatically generates thin bridges between islands.

As mentioned by @Aloisdg : It is a Processing project and it is hosted on GitHub.



I tested it successfully on the pavement last year. The pavement should be as slick as possible, though.