Different tiles at Passeig de Gràcia

These are the 2 sorts of tiles you can see in Passeig de Gràcia. 20 years ago only the larger could be seen. Then the City Hall changed the lateral curbs with the smaller. Why? Some claim the smaller is the original Gaudí design, while the larger was a later invention. Noawadays you can still see the larger in the central, smaller curbs in Passeig de Gràcia. Really elegant design for curb tiles!