Students communicate a sense of 4-D, motion, and/or time, based on creative use of spatial relationships and innovative treatment of space and its components. Instruction may include, but is not limited to, content in green or industrial design, sculpture, ceramics, or building arts. Students address 4-D, the inter-relatedness of art and context, and may also include installation or collaborative works, virtual realities, light as a medium (i.e., natural, artificial, or reflective), or flexible, entered, or activated space. Other concepts for exploration include tension, compression or expansion, intrusions or extrusions, grouping, proximity, containment, closure, contradiction, and continuity. 3-D artists experiment with processes, techniques, and media, which may include, but are not limited to, creating maquettes, casting and kiln-firing techniques, stone carving, mold making, or working with glass, cement, PVC piping, or structures scaled to human existence. Craftsmanship and quality are reflected in the surface and structural qualities of the completed art forms. Students in the 3-D art studio focus on use of safety procedures for process, media, and techniques. Student artists use an art criticism process to evaluate, explain, and measure artistic growth in personal or group works.