more teacher feedback
made a tinyurl for the students to access this applet more quickly
http://tinyurl.com/rgslens

I realized the virtual rays are still not "dotted" (or fainted) correctly.
The rays exiting the object should be solid ray (your red ray exiting object is fainted).
The rays entering the object from the image should be dotted and doesn't need an arrow head.

cheers!

[color=blue][b]need to understand what the teacher means
The rays exiting the object should be solid ray (your red ray exiting object is fainted).
The rays entering the object from the image should be dotted and doesn't need an arrow head.[/b][/color]