On the bandstand at the Kennedy Center Jazz Club, Stefon Harris' vibes run parallel to the edge of the stage and perpendicular to his marimba.

NPR: Stefon Harris And Blackout On JazzSet

In other words, when you think you are going straight and pointing your skis downhill and parallel, you are actually turning them both towards each other thanks to the edge pressure of your natural stance.

FORBES: Why You Need Custom Ski Boots - Now