The use of pebbles in flooring, both inside and out, is very common around El Maestrat from the mountains right down to the coast. They are generally inlaid into the floor amongst large smooth stones, but sometimes you will come across whole streets of them, even more awkward to walk on with heels as cobblestones are. The patterns can be exquisite and I call this pebbledash gone right, but in truth the Moors introduced the style to Spain and if you look carefully at the geometric designs, you can see the juxtaposition of the Koran with Cathar and other Christian influences.
The tradition of real pebble work has all but died out and it is hardly surprising. Though it is easy enough to do these floor inlays, the naturally-formed pebbles are hand-picked from beaches or dry river beds.
Just like the landscape-defining dry stone walls and terraces of the mountains, the man hours required to execute them are just not practical in today’s modern world. It is interesting though that you can buy machined mats of them now in most DIY places. Not as beautiful, but much more practical, and generally intended for shower floors.