Good Will Hunting is a story about Will (Matt Damon), a brilliant but selfish young mathematician who won’t open himself emotionally to others, due to a childhood of domestic abuse. A psychiatrist named Sean (Robin Williams) gradually develops a friendship with Will and breaks through the barriers Will has put in place, revealing the strength and kindness that results from true vulnerability.
Will and Sean meet a total of eight times throughout the movie, represented here by the eight panes of glass. Sean slowly breaks through Will's external barriers to reveal the true person inside. If you watch the movie, you'll understand why the third pane is blank and the seventh pane is broken.
The final setup. The design at the center is based on the painting in Sean's office which Will uses to accuse Sean of feeling vulnerable. Turns out Will is correct, but he doesn't realize until the end of the movie that vulnerability, far from being a weakness, is necessary for peace and happiness.
The final poster.