How the Circularize Function Works
The circularize function takes as its input:
a handle (circularize is thread safe)
an array of xy coordinates representing the vertices of the polygon you want to convert to a composite curve.
the number of vertices (makes sure to count both the first and last even though they share the same coordinate)
a chord error parameter
The output consists of an array of "elements." Each element represents either an arc or a segment. There are 5 data in each element. If the element is an arc the 5 data are: