A strictly linear 2D segment.
Think of LineSegment as a more limited representation of the Segment, . While both LineSegment and Segment are capable of describing straight lines, LineSegment is only capable of dealing with straight lines you'd generally only use LineSegment if you strictly want to work with problems in the linear segment domain.
LineSegments are easy to extend in length thanks to their simple two-point construction.
Start of the line segment.
End of the line segment.