We love this project! Moniker is a digital design studio in the Netherlands and for one of their recent projects they created 'Painted Earth'. This allows people to paint using the earth as a canvas. By logging into their phone and walking around, their movement becomes brush strokes - walk faster and the paint makes dots, stand in one space and it pools and drips. But it doesn't end there - up to 200 people can be in one place and 'paint' at the same time.
You can visit the project online here.