Barcelona floortile panot style mold form

When my wife and i went to Barcelona this year we fell in love with the floor tiles which are used there. We tried to get a couple of them to take back home as a reminder for our garden, but it was impossible, so we decided to do what every diy´er would do in that situation, make them ourselves. Maybe someone out there wants the same :) 
The tile should come outside as a 20cm x 20cm with a hight of 4cm, just as they are in Barcelona.