pie.endAngle([angle]) If angle is specified, sets the overall end angle of the pie to the specified function

stack.offset([offset]) If offset is specified, sets the offset accessor to the specified function or array

d3.symbolSquare The square symbol type.

d3.curveBasisClosed(context)

radialArea.curve([curve]) Equivalent to area

d3.pie() Constructs a new pie generator with the default settings.