Traditional black and white paving on Rua de Miguel Bombarda in Porto. Known as calçada, this type of paving is traditionally used on pedestrianised areas and squares.
This isn't the most flamboyant example you'll see in Portugal, you'll have to got to Lisbon for that, but it look nice - especially on Google maps!
Rua de Miguel Bombarda is fairly central and branches off from Rua de Cedofeita. It is known as something of a hub for art galleries and the likes.