Preset 
Primitives 
Arc 
Arcs can be either NurbsCurves or implicit curves (nonrenderable shapes commonly used to define paths, constraints, etc.)

Circle 
Circles can be either NurbsCurves or implicit curves (nonrenderable shapes commonly used to define paths, constraints, etc.)

Spiral 
Spirals can be either NurbsCurves or implicit curves (nonrenderable shapes commonly used to define paths, constraints, etc.)

Square 
Squares can be either NurbsCurves or implicit curves (nonrenderable shapes commonly used to define paths, constraints, etc.)
