Was thinking about something like that recently — recalling maybe some kind of art piece from a decade or two back?

1) Place a camera + display somewhere in an urban area of the world so that random pedestrians can come and watch the display, will be on camera.

2) Place any number of these identical setups in other areas of the world.

3) Arbitrarily feed the camera from one to the display of another (shuffle every 24 hours?).

You get people seeing/reacting to others seeing/reacting ... possibly to them, possibly to others who are seeing/reacting to....