On sunny afternoons young scofflaws defy Berkeley’s municipal code to munch pizza on the East Bay’s most scenic island — traffic island, that is. The grassy median, barely six feet wide, splits Shattuck Avenue down this most hallowed block for foodies, starting just about where Chez Panisse begins and stretching north less than half a block to Vine Street. At nearby outdoor tables at César and Taste, diners rack up big credit card numbers to bask in Gourmet Ghetto sunshine. But if you’re willing to flout the Keep Off Median sign, you can bask in the same rays for $2.25 — the cost of a slice of the daily-changing, lovably oily veggie pie from Cheese Board Pizza. Join brainy Cal girls in stripy summer dresses; cute, shaggy dudes in Urban Outfitters tees; and the whoosh of cars and AC Transit buses just feet from your face. Somehow, the exhaust fails to spoil either the view or the taste of the pizza.