KCABDEEF

I really like it too. I see a direct evolution from the Cows to the Red Ball to the Bullhorns.

The cows just sat there looking stupid, somehow attracting tourists, while being an obviously transparent attempt to sell "Chicago". The Red Ball is just as playful, but encourages interaction, appears more intrusive, and sadly, by the time it hit Chicago was being sponsored by Target in a transparent attempt to sell things.

(for the record, I think the green shirt people have sparked good thoughts, so I don't regret choosing that image, but the people in green shirts actually don't have anything to do with the Red Ball project. There are plenty of greenshirtless (most in fact) people that experience the ball daily in its various locations.)

And the bullhorns, are again a playful insertion into the city, but a bullhorn grid would provoke interaction instead of teasing it out of people.

Here's how I see it.
1:Kid sees bullhorn grid.
2:Kid asks mom if he can say something into one.
3:Mom says, "no, I'm not sure if anyone is allowed to, it's just art"
4:Kid says please
5:mom looks around, and thinks, "well maybe that's what its for", says "okay, but be quick".
6:Kid says, "HELLO" into bullhorn, sound is amplified, laughs.
7:mom laughs.
8:some drunk high school kid walking back from blues fest leans over behind another of the bullhorns and says "VAGINA". Laughs, looks at his laughing friends and says "FUCK THIS". Thinks he is hilarious.
9:Mom goes over and scolds high school kids, saying "that is not what this is for".
10:Bystander, thinks mom is absolutely wrong, but doesn't want to say anything.
11: another bystander sees the bullhorns leans behind one of them and says, "THAT"S EXACLTY WHAT THESE THINGS ARE FOR........DAMN HELL FART"
12:Mom grabs her son, and walks away in some mixture of rage and embarrasment. Learns valuable lesson.
13:Designers of the bullhorn grid look on at the feedback loop of communication they have created.