I was running laps on a sidewalk that went around a mansion. On one side there were a set of stairs. The stairs were split in a way that 1/4 of them on the left side were slanted down, so it would be easier to climb. During the 1st few laps, when I would approach the stairs, I took the right side. Eventually it became too tiring to use the right side, the stairs were almost impossible to climb, and I even fell backwards when I tried. I soon gave up trying and used the slanted side. It was so much easier, like I was skipping instead of walking up stairs, almost no effort. As I did more laps, I only used the slanted side from then on.