Install digital white walls(could be one or more) in the main streets for the people to paint with their smartphones or tables; if they don't have device, they can take the digital brushes available in the place.
All the user's paintings will be saved in a central server for this project to be shown at the online platform to share, receive comments, open discussions, etc), also people can share them LIVE in their social networks accounts directly from their mobile devices.
As an option, maybe, users can also paint the wall directly from their devices LIVE everywhere they are and then they see it at the online platform(in this way the paint wall remains alive in the urban place and online).
Inspiring reference links:
more touchscreen links:
- $10000 - 15000 per wall
- $20000 online platform and technology