At first, Marie Watt’s decision to use blankets as the principal medium in Tread Lightly, her current show at PDX Contemporary Art, seems a little curious. Then again, most of us formed one of our first intense attachments to a blanket. And it’s easy to see why: All the psychological value a blanket offers – warmth, security, protection – is embodied in sensuous physical terms. Although Watt builds off this near-universal connection to blankets, her assemblages also gain meaning from an exploration of materials and art historical references.