A young John Nash observes a strange ceremony in the Princeton faculty club. A professor is being handed pens by his colleagues. It's a mark of respect, a recognition that a professor has made a major contribution to the field of mathematics.
Many years later, it's the turn of Nash, who's now become a mathematician of some renown, to be honored by the pen ceremony. His colleagues silently approach him and present him with their pens in recognition of his enormous contribution to the subject. This is a sign that Nash has finally been accepted by his peers, that they respect him for his many great achievements.
The pen is an apt symbol for such an honor as it represents the power of creativity, of invention. Just think of all the great contributions to humanity—novels, poems, scientific papers—that have been brought about by the use of this humble writing instrument.
Now that Nash has been honored by his peers he has joined the select company of those great mathematicians of the past who contributed so much to our understanding of the world.