Steve Martin and Harry Bliss on the concise joy of cartoons

The multi-talented Steve Martin has covered a lot of ground, as a standup comedian and actor, writer, novelist and musician. Now he can claim "cartoonist" to his resume, collaborating with noted New Yorker cartoonist Harry Bliss on humorous one-panel gems. Correspondent Mo Rocca talks with Martin and Bliss about the precision of the cartoon; capturing ideas in the middle of the night; and their cartoon collection, "A Wealth of Pigeons."