The instructors presented another comparable foam board that had a fan hooked up by tape with wires that extended from the fan (fan-board) reaching over the sides of the foam board. The instructors showed that when the observe was tilted to make a slope, the foam board would levitate and glide down the slope on account of gravity. This means the bike (or treadmill, or elliptical - they’re all the same concept) will increase resistance for a while (to mimic you riding up a hill), then ease it off...