At Mosaic Preparatory Academy in Harlem, New York, reading, writing and arithmetic are not the only subjects on the curriculum — so is being nice.... ...When 5-year-old King Ortiz was pulled out of class one day, he knew he'd earned something special — coupons for nice behavior that can be redeemed for tokens. "I learned to be nice," King said. Twenty-five coupons score students a shiny token for the vending machine. Tokens go in, but no chips or candy come out — only books drop....