 He also added the "New Yorker's" squiggly column rules; these provide a delineation between the text and illustrations.He was also responsible for the vertical "cover strap" that was used for the magazine's margins.According to James Thurber, "the invaluable Irvin, artist, ex-actor, wit, and sophisticate about town and country, did more to develop the style and excellence of "The New Yorker's" drawings and covers than anyone else, and was the main and shining reason that the magazine's comic art in the first two years was far superior to its humorous prose."