Sculpture exists in the world we ourselves occupy. However sculptors have a variety of formats to follow. There are three types of spatial experiences: relief, in-the-round, and installation. Sculpture in relief is only three-dimensional with real hills and valleys on one side; the back is flat. Relief sculpture is akin to a “bumpy” framed painting. Sculpture in-the-round is self-supporting, standing on its own “feet.” It must employ ponderation, have an adequate balance of weight to prevent toppling. Sculpture in-the-round must be finished on all sides so the viewer can walk around it. Installation sculpture is also free standing but the viewer can actually enter into it and totally experience it.