I've found via Balla Dora Typo-Grafica an exciting work made by Sagmeister Inc..
In September 2008 Sagmeister Inc. partecipated in Droog Event 2: Urban Play by DroogDesign. The public art installation consisted of 250.000 eurocents placed on the floor, covering more than 300sqm on a square in Amsterdam. The coins spell out the sentence “Obsessions make my life worse and my work better”. The piece was part of the series “Things I have learned in my life so far” by Stefan Sagmeister. The design has been created using four different shades of pennies. They first sort them by color, then lay them out on the tiles. You can download the original design (zip, 4.4MB). After the piece was completely set up they will left it alone, on the street. They expected the piece to slowly dissolve as people take coins, play with them, alter the design. All coins have been painted on the back with a bright blue permanent color.