Beauty, thy name is Mambo for Cats. Permit us to explain: At City Diner, the sunny South Grand snack stop that manages to be both hip and unpretentious, the walls are covered with film posters and album art. Most of it's seen-it-before dcor, but on the south wall is an extraordinary record cover: Mambo for Cats. The titular cats, rendered in what we can only call "Sesame Street cubism," are mamboing like there's no tomorrow, rolling on their backs, standing on their hind legs, pounding on a set of bongos. It is beneath this grand piece of music history that we have chosen to consume the finest BLT in town. Though the menu listing"BLT...$5.50"is humble, this sandwich should be called a BBBLT, so abundant is the bacon. Whole-grain bread, toasted hazelnut-brown. Thick, summery tomato slices. Crisp romaine lettuce. Add a buck and you can get hand-cut fries (and you should). The going rate for a pressing of Mambo for Cats? About 70 City Diner BLTs.