Singapore Biennale 2008 is here and the above picture is just one of the many arts installation all around Singapore, particularly in the Heritage District area.
It is called Fantasmas (Phantoms) by Isaac Montoya (1963, Burgos, Spain). There are actually two filters (red and blue) which I didn't capture in my picture. But when you view the picture through the filters, the different colored filter will show either a happy or sad image. I guess this works through the diffusion of colors or something?
Check out the website for more information on the other exhibits or events. It is from 11 Sept to 16 November 2008.