Up on the 10th floor, around the corner to the left as you step off the elevator, the Seattle Central Library’s atrium outlook comes to a dead end, jutting out over . . . nothing, except a lot of space. One small leap over the railing and you could splat right onto New Fiction down on 3. (That belly-high gridded railing feels sturdy to the touch, but looks kind of like a chain-link fence made out of aluminum foil.) Surrounding you is the crosshatching of baby-blue girders that form the building’s exoskeleton; overhead is a padded (why?) white ceiling. Backing away, you’re startled by the yawning elevator shaft; all that separates you from a plunge is a glass wall that may as well not even be there for all the feeling of security it gives. But the best part of the Outlook is that there’s no reason for it to be there—it’s just a playful fillip in Rem Koolhaas’ design. GAVIN BORCHERT 1000 Fourth Ave., 386-4636, spl.org