There’s a closing reception on Saturday for Joshua Primmer’s show at Arch Contemporary, the small ceramic gallery and studio that’s consistently the edgiest thing about Tiverton Four Corners. (Sorry, ice cream llamas.) Primmer had a summer residency at the studio, just after completing his MFA in Ceramics from RISD, and the resulting works range from functional mugs and vases to these fascinating spacy black objects that resemble mysterious stone tools from some post-apocalyptic future.