When longtime Denver art dealer Robin Rule died last year, a trio of faithful assistants — Valerie Santerli, Rachel Beitz and Hillary Morris — decided to resurrect her namesake gallery and carry on her legacy. The new Rule Gallery, inside Hinterland, is small and informal, but it meets the minimal requirements for an exhibition space for first-rate art. One of the earliest shows there was Joseph Coniff (in parenthesis), an elegant affair made up of the artist's chic-looking post-minimal paintings. Though his color choices were unnatural, the paintings conceptually evoked landscapes, as each was divided into three broad horizontal bars that easily stood in for foregrounds, mid-grounds and backgrounds. This was in spite of the fact that the Coniffs were utterly flat, with no illusion of depth whatsoever. Because of the high quality of its presentations, the new Rule is a worthy successor to the old one.