This is an interactive installation that I worked on back in the year 2008. It was a great experience when setting it up. Because it's a outdoor installation, so the setup took us about 3 to 4 days to get it right.
Behind the scene:
This is probably the biggest desktop I've ever seen, two huge board has merged together to fit the horizontal screen. 
And the machine was place in a small room about 200 meter away from the projection, it's really a headache for me that time to check the alignment instantly, so my colleague, Boyle has to become my "eye", monitored the projection, and yet yelling to me about how things going. 
Part of the interaction scene, it's four season themed and this is the spring part, the dandelion grows at the bottom of the projection, and everytime people pass by the dandelion will let go. 
--Just like this. And it feels so great to try it out by myself. It works perfect when day gets darker, since it tracked and interacted with black color. So it either goes with the dark color shirt, or the shadow that casted to the projection, and it went flawless! 
Autumn, the leaves falling down and people get to gather the leaves. 
Another shot for the snowing scene. Everything seems so perfect. 
Party on!