Chairs, stool assemblies, and systems for constructing furniture. Such a chair including structural members having hinge joints at ends thereof pivotally coupling each of the members to one or more adjoining members. The chair is configured to be arranged in a collapsed configuration wherein all of the members are in the same plane and define a substantially planar shape, and configured to be arranged in an expanded configuration to define a seat, armrests, support legs, and leg braces of the chair. Such a stool assembly includes at least first and second stools configured to be stackable such that the seats of the stools abut face to face and in combination define a composite base. Such a system for constructing furniture includes multiple joints each having slots configured to receive and retain structural members and configured to be assembled with the structural members to form a piece of furniture with the multiple joints defining corners of the piece of furniture.