A Puffy 90s Style Inspired by the Past, But Built for Today. The Knu Skool is a modern interpretation of a classic 90s style, defined by its puffed up tongue and 3D-molded Sidestripe, and tied off with chunky laces. With its in-your-face profile and dramatic style details, the Knu Skool plays off of the original Old Skool while blending an icon of the past with today’s trends.