An Edge2 provides several neat methods. The most obvious will be draw():
line1.draw(PURPLE ); // draw a purple line
line2.draw(GREEN, 0.1); // draw a green line, with width 0.1
line3.draw(GREEN, RED); // draw a line that starts out green but fades to read
Other methods of interest are center(), delta(), dir() and length(). All of them can be found in ⇒ Math ⇒ Shapes ⇒ Edge.