Playing with the concepts of indoors versus outdoors, public versus private, and mansions versus housing projects, Boston-born artist Liz Glynn’s “Open House” installation, organized for Boston by Now + There following a stint in Manhattan, puts forth a Gilded Age era ballroom in ruins. The installation is composed of 26 cast concrete pieces, including arches, as well as Louis XIV chairs, sofas, and foot stools on which you may sit. Organizers hope the exhibit sparks conversation of economic disparity. Bonus: There is another sprawling installation by Glynn currently on view at MASS MoCA. “Liz Glynn: Open House,” on view through Nov. 4 on the Commonwealth Avenue Mall between Kenmore Street and Charlesgate West, nowandthere.orgMarni Elyse Katz blogs at stylecarrot.com.