The Sign Guy won't tell you his name. But from one bar stool to another he might tell you a piece of his story, or talk about the paintings he's been putting up on fences and poles around Tremont. He acknowledges that it's a little bit flattering when someone steals his work, but it pisses him off, too. Because when he puts up a picture, he takes a risk. He could get in trouble for that. It wouldn't be much, just a minor misdemeanor violation of the city's ordinance against posting bills, but still. When someone takes it down, they don't face any chance of getting in trouble. He knows people collect his cheery pictures of birds and flowers and worms with wings, but since he goes to the trouble of putting them out in public, he wishes they could stay up for a while. He calls it Free Art.

So he's taken steps to secure things. He keeps a cordless drill and some screws in his car, along with a supply of his hand-painted signs — pictures of birds and flowers, painted with spray paint and cheap mis-mixed latex house paint, on scraps of plywood or old metal signs. To guard against theft he doesn't use regular picture hooks or tack them up with a nail. When he's going to hang something on a phone pole, he'll get out the drill and drive four or five screws deep into the wood. If you want to take one of these, you'll have to work.

Another technique is a little more extreme. The Sign Guy works as a machinist, so he's familiar with working metal. And he got a guy at the shop to show him how to weld. This is good for attaching chains and screw eyes and other loops of steel to his metal signs. If he finds an open padlock - which he does now and then — he'll use that to clasp a sign to a post or a cable or a fence. As far as practicality is concerned, there is no key to take these down. He's got at least one picture of city workers wielding man-sized bolt cutters to clean up his goofy litter.

The Sign Guy is not a subtle painter. The images are flat and two-dimensional, without shading or any complication. Black outlines are filled with solid shades, coloring-book style, occasionally given a contrasting halo that follows the black outline like a neon echo. The Sign Guy says he learned his style from "learn to draw" books, which give directions like, "first, draw a circle for the head. Now, make triangles here, and here, for the beak and wings."

He keeps his name a secret because he used to write the name of a big black bird on train cars. He got busted for that once, walking out of a rail siding in Euclid. He says he sat in jail a couple of days "because they didn't know what to do with us." That was in 2005. Trespassing with the intent to commit a felony, and breaking and entering — because he went around a fence - cost him a year's probation and some community service, and he had to pay $1,000 to CSX. So he gave up painting, until a friend gave him some brushes and told him to work in a different medium.

He figures he's put three or four hundred of his simple paintings up around town, mostly around Tremont. His name, the Sign Guy, came when someone posted on a Tremont blog, "Who is the Sign Guy?"

Some of them could be called public service messages: "Drink Drive Die" is one of those panderingly simple equations: a martini glass plus a car equals a skull and crossbones. He recently did a set of stenciled signs - the same size and shape as the city's official No Parking signs - and attached them to some of the same sign posts, warning people to "park at your own risk." They are illustrated with human figures and cars. Some are political - like the ones that illustrate the phrase "war pigs" with naïve, curly-tailed, pink pigs.

The most typical, though, are simple birds peeking from little plaques on phone poles, or posed in an urban morality play of situations: A "bad bird" in a black mask robs two birds, which seem to be mother and child, at gunpoint. Good and Evil birds — one with a halo, the other with devil horns and a tail - face off back to back, apparently hatched from the same egg. Or a pink bird wired to a chain-link fence overgrown with vines, the bird chirping the message that whatever grows there is "safe to eat." One piece has a bird painted on a television, happily urging "kill your TV," his beak opened wide in song. Some of the signs are painted on large banners. These most commonly get wired to the chain link fences where bridges cross over I-90, I-490 or I-77. In one of these a bird chirps, "Go Tribe." In another he reminds that "Jesus Saves."

He has another artistic vein, examples of which can be found in occasional gallery shows, which he's had at Visible Voice Books and La Bodega in Tremont. Those have a darker, grittier quality and use a gothic and sado-masochistic vocabulary of images. But he doesn't put those up around town. He has, it seems, an inborn respect for community standards, even as he wages his guerilla redecoration campaign.

Just like the appeal of illegal graffiti, appreciating the work of the Sign Guy is complicated. The work he does hang around town gains a tremendous amount from its context and presentation. With the bright simplicity of children's book pictures, they contrast against the chain-link, concrete and rusty industrial landscape: a quick flash of color and hope. And, attached with bolts and chains under cover of darkness, they have a mischievous quality that can't be brought indoors. Anyone who steals his work from public installation is robbing from the city and getting an incomplete prize, removed of the situation that defines it. It's like trying to steal an entire painting and having only a little piece tear off in your thieving hand. Even if it's technically true, it would be a stretch to argue that his work is vandalism or defacement or in any way malicious. Rather than painting on someone else's property, the Sign Guy has figured out a way to add color and humor to the city without actually doing damage — accessorizing the neighborhood with jewelry rather than tattoos.

The Sign Guy: La Bodega, 869 Jefferson, 216-621-7075.

Tremont Artwalk: 6-10 p.m. Friday, June 13. Various locations.