Web exclusive: Cartooning with 'Doonesbury' creator Garry Trudeau

Watch CNN's Jake Tapper and Garry Trudeau draw memorable "Doonesbury" and other cartoon characters in the video above.

Tapper draws three characters from his college comic strip "Static Cing" for Trudeau. The CNN anchor named his main character "Garry," for his idol at the time - Garry Trudeau.

And Trudeau draws for Tapper the character that started it all - football player "B.D." Trudeau said "B.D." started as a one-off sports script called "Bull Tales."

The character B.D. has gone through many changes in the last four decades, the logo on his helmet changed from "Y" - for Trudeau's alma mater Yale University - to a star when he went national. He later served a tour in Iraq, where he loses a leg, and then sought help for post traumatic stress disorder. Military challenges, such as wounded warriors, and sexual assault, are frequent story lines in "Doonesbury."

One constant character - and Trudeau's favorite - is "Zonker." His style, said Trudeau, has not changed much since the old days.

Another character Trudeau said has "had more than his fair share of space in the strip" is "Duke." Duke is currently running a lobby firm for a disreputable authoritarian. He lives in an apartment with "President Triff from Berzerkistan."