I didn't know which category to choose so I took a chance here. This sculpture represents what's called in Portuguese "Calceteiros", the traditional pavers. They would make all the patterns like the one shown here. It's a craft that is disappearing or even already gone. The one on the right would break and shape the stone, creating the patterns like the one you see here and many that can be found all around Lisbon and other cities in Portugal. The worker on the left would press the stones down. The pattern you can see here is the symbol of Lisbon City.
It is very impressive. However it is a mosaic, not a sculpture.
There are two sculptures. The photo, as usual with me, is posted sideways, I don't know why. If you look at the top of the boat you'll be able to see them.
@Paddypereira I see it now; thanks for the correction.
As for your photo, the site seems to believe all photos are shot in landscape.
@MsKathleen, it's a bit of a nuisance not being able to post photos properly but there are things a lot worse that we have to put up with. So I'm happy that someone appreciates this little thing.