The x-coordinate of the arc’s control point. The control point is best located about halfway between the beginning and ending vertices of the arc. Otherwise, the arc may grow to an extreme size in order to pass through the control point, with unpredictable results.
The ratio of an arc’s major axis to its minor axis. Despite the usual meaning of these words, the major axis does not have to be greater than the minor axis, so this ratio does not have to be greater than 1. Setting this element to a value less than or equal to 0 or greater than 1000 can lead to unpredictable results.