Otto Piene at Sperone Westwater

Otto Piene’s retrospective “Sundew and Selected Works 1957-2014” includes several splashy installations (the title piece, a bright red inflatable created in 1970, on view for only the second time, and one of his twinkling “light ballets,” projected in an upper gallery). But it is the Zero group cofounder’s more subtle works that are most enthralling, like his Rasterbilder (screen pictures), which involve forcing paint through perforated screens, creating textured, monochromatic—and sometimes metallic—canvases, and fire gouaches, made late in the artist’s career.