Seattle-based architects and artists Daniel Mihalyo and Annie Han, who collaborate under the name Lead Pencil Studio (leadpencilstudio.com), have built their reputation on nothing. More specifically, their award-winning site-specific installations have focused on absence—such as in 2003’s “Stairway,” a spindly metal flight of stairs missing quite a few steps in the middle, and 2006’s phenomenal “Maryhill Double,” a full-scale replica of the Maryhill Museum of Art made only of scaffolding and netting, which faced off with its namesake across the mighty Columbia River Gorge. Their newest work, “Non-Sign II,” is no less arresting: a billboard, or, rather, the absence of a billboard at the U.S.-Canada border crossing in Blaine, Washington. (The permanent installation was commissioned by the U.S. General Services Administration’s Art in Architecture Program.) A double-take-inducing 50 feet long by 30 feet high by 3 feet deep, the web of tiny stainless steel rods hijacks a standard of advertising and reworks it as a live weather report, a bird showcase, a portal between nations.