They sprung up a few weeks ago in two vacant lots at North Williams Avenue and Fremont Street. Rectangular, boxy, about tall-man-high, a fetching shade of bamboo green, emblazoned with directions to nearby streets, parks, TriMet, the airport—uh, what are these things?

With their chipper descriptions of Irving Park, the Mississippi hipster strip and the Fremont Bridge, the pods of mystery look at first like a bit of city-funded boosterism.

But in fact, they're private advertising: a cleverly muted stealth promotion for two major mixed-use developments coming soon to this heavily trafficked but desolate corner of North Portland.

"I've seen people stop and walk around them like the scene from 2001," says Ben Kaiser, the developer responsible for the half-dozen green "monoliths." "I like the sense of mystery. The idea was to give people a reason to stop, get out of their car and engage with the site. This intersection is a hub for so many things, but people tend to just put their heads down and...blast through here."

With three major streets, an Interstate offramp, bike lanes and stops for some of the city's busiest bus routes, this should indeed be a hopping corner. Instead, its current emptiness testifies to decades of disinvestment in the once-thriving Williams.

Kaiser's monoliths—without saying so—herald huge changes at the intersection, part of a wave of development surging up Williams and its sister street, Vancouver Avenue. The developer plans a 41-unit live/work complex with 8,000 square feet of commercial space and 39 loft-style condos on the kitty-corner lots. With an 11-month construction schedule set to begin in August, the weeds and bark mulch now occupying this prime land will soon be history.

For now, though, the place is more art than commerce.

Designed by Keith Warner of the local firm Big Giant, which also created packaging for Nike's iconic Livestrong bracelet, among other projects, the monoliths are simple plywood boxes skinned with adhesive vinyl. Warner says his bold, easy-to-read graphics highlight things about the neighborhood that commuters probably miss as they race off I-5 or lumber along in the No. 4 bus.

"We liked the fact that Ben wanted to call attention to the whole area, and not just this particular property," Warner says. "It's intended to be sort of a wayfinder, to identify some specific locations or specific facets of this location that may have been lost."

To Kaiser, the temporary installation speaks to the broader aims of the buildings he'll build. The live/work building will be the first to take advantage of new definitions in the city building code aimed to encourage the notoriously tough-to-build format.

"For years, I've wondered about this corner," he says. "You're right at the center of Mississippi, Alberta, Killingsworth, Fremont, Broadway—all these major streets. And yet here, it's just blight. There's no sense of place. But it's in a place, and I think the mixed nature of this project will be reflective of this area. This isn't the Pearl, and it's sure as hell not South Waterfront."

As real estate advertising, the Williams monoliths may be uniquely low-key. As signage, though, they seem to have attracted just the kind of puzzled, intrigued interest Kaiser hoped to drum up.

"They're asking if the city is responsible," Kaiser says. "We had one tagger, but it was almost a respectful tag—small, like he didn't want to interfere with the graphics."