/Polyline ... /EndPolyline describes a polyline, i.e.,
a set of successive line segments.
A List of vertices is described between
/Polyline and /EndPolyline.
The following is the format of describing a polyline with
N vertices, i.e., N-1 line segments.
| Format | /Polyline |
/PLVertex x1 y1 z1 |
|
/PLVertex x2 y2 z2 |
|
| ...... | |
/PLVertex xN yN zN |
|
/EndPolyline |
|
(xi, yi, zi) |
the i-th vertex position |