The Art of Gratuitous Praise

On the other hand:

Ding! "You are always there when needed."

The machine calls to Tom Minter, 50, a resident of Q Street, who walks past the corner regularly. "It really makes you feel good," says Minter, a playwright. "If I'm having a really bad moment while I'm walking down this street, and it penetrates the fog, it's a good thing."

Ding! "Your eyes are beautiful."

The machine calls to a heavily muscled man in a snug black T-shirt, who pauses for just a moment to frown at the machine before heading on his way.

The Compliment Machine knows as much about its subjects as a fortune cookie knows about its eater. There's no science to it. Greaves simply read a hundred compliments in his most neutral voice -- like the recordings telling people to watch for the end of the moving sidewalk in an airport -- and put them on an iPod Nano. The Nano is inside the machine, plugged into a speaker and powered by a car battery (Greaves removes the iPod at night so it doesn't get stolen). The compliments play at random, and every night Greaves changes the compliments a bit, adding some and removing others. The machine operates from about 10 a.m. to 7 p.m. each day through July 27.

Between compliments is a gap of silence lasting several seconds to several minutes, to heighten the anticipation. Greaves picked up the idea at the Pompidou Center in Paris, where he observed a dummy with a bell hanging by its head; every few minutes, the dummy would lurch forward and bash his head against the bell.

Initially, Greaves thought of making some of the compliments subversive, but had a change of heart. "Why not make it completely positive? Everyone deserves to have a compliment paid to them."

And so the Compliment Machine has kind words for even the blackest of hearts. "Maybe if the compliment doesn't apply to them, they'll want to change that," says Greaves. Like a horoscope, there is the potential that the compliment becomes a self-fulfilling prophecy. If the machine says "You leave things better than you find them," then maybe, just maybe, the recipient will be inspired to improve one little thing.

But it's hard to catch a break in this world. When Greaves went to install the machine earlier this month, he was across the street from a crew of construction workers.

"You are a wonderf--" BUZZZZUZZZZ! A circular saw loudly interrupted the machine -- unintentional commentary, perhaps?

How difficult it is in this modern age to hear those rare words of praise over all the chaos of our lives.

"You have--" PRAP PRAP PRAP PRAP!

Or perhaps it's just the reality of public art on a bustling street in a gentrifying neighborhood in a busy city. In response to the noise, Greaves ratcheted up the volume of the machine so that, after a long day or week or month or year, a person pausing at the corner could hear:

Ding! "You're a star in the face of the sky."