Guess what is it? Number matrix. The great thing about it if you follow the red marking, the total will be 33. There is so many patern to make up such a magic number. It was engraved at the Segara Famille ( a catherdal that is still under construction after 100 years) in Bacerlona, Spain. One of many Gaudi master piece. The new wing at Segara Famille is build by different architect with modern art.