An article of furniture can include an upper beam member, a first side member, a second side member, and a plurality of attachment bracket members connecting the first side member to the upper beam member adjacent a first side of the upper beam member and also connecting the second side member to the upper beam member adjacent a second side of the upper beam member. Each attachment bracket members can have a body and a plurality of arms extending from the body. The arms can include a first and second top arms, first and second intermediate arms, and first and second bottom arms. The arms can be positioned to define channels.