Make Line Bounce when Axis hits

I made a user input line plot. I want it to simulate a laser beam. Once the user clicks, the line is set and it's plotted. I want the line to bounce off and move in the opposite direction once it hits the right and left y-axis. I want it to do the same for the x axis at the top. Any ideas and/or pointers? Thank so much

Answer 1

[Image Analyst]

See code I gave in my other answer