As I mentioned on our Facebook page, I have mixed feelings about these lovely tiles (What Will Lisbon do About its Stunning-Yet-Dangerous Sidewalks?) which can be found in almost every city and town in Portugal. They are easy to pry up to perform road/sidewalk maintenance and are used to form the most amazing geometric patterns, but they have their downsides. When it's wet they're slick and I know when it rains not to wear one particular pair of shoes or I have zero traction.
They're also uneven and I still don't know how these ladies in heels manage to get around without screwing up an ankle. I've warned certain US friends who have mobility issues that Portugal might not be the best choice for them to visit. Certainly it's not just Portugal (most of Europe is like that) but it's not something tourists usually think about. You just don't go wandering around without paying attention to where you're putting your feet.
But they're pretty and unique. So what to do?