I'm Thinking!

I have a problem.  It started out innocently, but now it has turned into a little bit of an addiction.  I love puzzles.  Not the jigsaw type; the brain-teaser, logical-mathematical type.  I have become slightly obsessed. 
You may blame my new fixation on the teacher education program at my college.  This year I have to take a course in teaching mathematics.  Math has never been my strong suit, so when I realized that I would actually have to teach people math beyond 2+2, I kind of panicked.  I have to learn more math!  Right now!  I have to become a math genius!  So, in order to expand my logico-mathematical intelligence, I have started doing puzzles. 
Unfortunately, one of the characteristics that my math textbook says a mathematically literate person must have is persistance.  And I have taken this to heart.  I'm losing my mind, people!  I can't solve the box problem!  I must give up!  But I can't!  I must be persistant or I will never be a great math teacher!  My career depends on solving the box problem!
Ok.  Breathe.  I can do this.  Can you do this?  Check out the box problem at the site below. 

The box puzzle. Follow this link, scroll down, and click play.  

 
T