For weeks, I've been watching this strange structure take shape at the east end of the Hawthorne Bridge and thought, "What is that?"

It's art, of course. Part of the art installations going up along the new Eastside Streetcar line, funded by the city's 2% for Art program.

The strange structure is a ghost building, a matrix of steel that resembles the exterior of an industrial building that used to be on the site: The Phoenix Cast Iron Foundry. The piece, called Inversion: Plus Minus, is designed by artists Annie Han and Daniel Mihalyo of Lead Pencil Studio. As Southeast Industrial gets more hip, I think it's great to see art referencing the manufacturing history of the neighborhood. Cast iron construction boomed in Portland when the city first started getting big in the 1850s-1880s and you can still see a lot of cast iron in town, mostly downtown on historic buildings that have been restored. Here's a blurry aerial view of the old Phoenix Foundry from when it was in operation.