When you enter the exhibit hidden behind a black curtain at the Bolinas Museum, a glowing blue sea urchin six feet in diameter emerges from a wall. From inside the hollow sculpture come ambient recordings; they sound at times like a buckling bridge and a spaceship zooming through a galaxy. A slit of light along one wall illuminates bottle caps; beside it, a tree knot encloses a diminutive video just a few square inches. The…
Charlie Callahan and his sea urchins