At CART High near Fresno, there is no gum stuck to the floor. The saffron-yellow walls are unmarred by graffiti. Toting laptops, students file calmly down spacious, light-filled hallways to classes like biotechnology and digital marketing. There’s no fighting, no shouting, no bells. No one even cuts class. It’s hard to believe CART High is a public high school. But in the future, this may be a model for every high school in California. “We can see from the data that the big, old-fashioned