title: turn a line into a rectangle
body: <p>I have a method that draws a line between two points.  This works pretty well, but now I want to make this line into a rectangle.</p>
  
  <p>How can I get the points on the left and right side of each of the line points to make it into a rectangle that I can draw?</p>
  
  <p>It is almost as though I need to somehow figure out how to get perpendicular lines programatically....</p>