The Center on Contemporary Art (CoCA) has an uneven record with its outdoor Heaven & Earth exhibitions at Carkeek Park, mainly because the works are almost always vandalized. (One year, a maintenance crew even removed a wooden hanging sculpture by accident, mistaking it for trash.) In its sixth edition, this year’s theme is “As Above, So Below,” a nod to myth and notions of the underworld. Most of the 16 pieces (by mostly local artists) are made of humble or durable all-weather materials: wood, metal, scraps, fabric, and so on. Some refer to the park setting, but few make you see it differently. The notable exception is Megan Treasure ’s Earthly Obscura, which mounts a camera obscura lens and viewing portal—through an old diving mask—on a conical mound that resembles a big red African anthill. The lens points west, not quite in view of the ocean, but it’s positioned to collect maximum western light, right up to sunset. It inverts the landscape, creating a haunting double image—or actually a quadruple image when it reflects from lens to iPhone to diver’s mask and back. That’s how I took this accidental selfie of my gnarled finger and ugly mug; I became a ghostly observer in Treasure’s antipodal realm, an unwelcome spectre. One almost wishes that there were 15 more such Stygian viewing stations deployed throughout the park, more shadow boxes to complement the sunlight. Carkeek Park, 950 N.W. Carkeek Park Rd., heavenandearthexhibition.org. Free. 6 a.m.–10 p.m. daily. Ends Oct. 20.