I used to live in a large apartment in the neighborhood of Sant Gervasi, with a beautiful sunny terrace. In the center of the terrace there wa a bench which had, in its back, a sink with a faucet. The point is that this bench/fountain had been covered using the Trencadís ceramic technique.
You can still find Trencadís in Barcelona in many existing buildings, although it is really a typical technique of modernist architecture. It was first used in the latch of Güell farm in Pedralbes Avenue, almost out of necessity, since the sinuosity of this latch forced to break the tiles into small pieces to make them fit. I must say that even though Gaudí is considered the inventor of the technique, it was actually developed and improved by Josep Maria Jujol, who collaborated with Gaudí himself in the design and construction of the benchs of Parc Güell, for example.
If you look carefully, you will find many examples of Trencadís in Barcelona, in public and private elements. It is just another of the marks that Modernism has left us and we have incorporated almost as a sign of identity.