The little side streets are paved with cubes of stone, perhaps 15 cm on a side. I saw a crew lay them down. They smooth out a bed of sand with wooden scrapers, then place the stones in arcs (not straight lines). Afterwards, they pour fine gravel on top, filling in the cracks, and sweep it off. It looks nicer than asphalt, is semipermeable to reduce storm water runoff, and can be easily and invisibly patched when you have to dig it up to get to water pipes. The stone chunks also don't require fossil fuels, unlike asphalt, cement blocks, or clay bricks.