Plane - A flat surface on which a straight line joining any two points on it would wholly lie.
"Cubist Guitar" by Sara Allison
"Untitled" by David Smith
"Cubist Sculpture" by Josef Hoffman
Modern sculpture by Tony Smith
"Split plane Sculpture" by Christopher Georgesco
Edge - The outside limit of an object, area, or surface.
"Untitled" by Robert Morris
"Cubist Sculpture" by Edward Allington
Cubist Wall Sculpture by Chris Coleman
"Woman" by Pablo Picasso
"Man With Guitar" by Jacques Lipchitz
Freestanding - Not relying on or linked to anything else.
"Figure" by Jacques Lipchitz
"Monarch Lady" by Lindley Briggs
"Big Blue" by Nancy Cervenka
"Totem Grove Series" by Ana Mendieta
"Sculptural Bird" by Katherine Harvey
Form - Visible shape or configuration of something.
"Playground 2007" by Tom Otterness
"Speed" by Hans Christensen
"Spherical Form" by Hans Christensen
"Discoid Form III" by Lucien Den Arend
"Leaf Form II" by Peter M Clarke
Closed Form - Self contained, 3 dimensional object.
Car by Chris Gilmour
"Agora" by Magdalena Abakanowicz
Signature Work by Emily Floyd
"Bravo" by Linda Benglis
"Life Underground" by Tom Otterness