I did make other experience with this function:
Here, swf_shapelineto doesnt set the given values to the
current position. In case this would not build a rectangle -
but it does.
swf_shapelineto — Draw a line
Draws a line to the
coordinates. The current position is then set to that point.
x-coordinate of the target.
y-coordinate of the target.
No value is returned.