Tapping the Line

Wait, what? My toes wiggled. I was frozen with my thumb sticking out, but then my knee bent all by itself. I looked down at the smooth white ground beneath me. There was a faint gray line tracing right along the curve. Why was that line there? Confusing, honestly. I lifted one foot and gave the line a quick tap with my shoe tip. Tap! It was solid. My legs felt springy and totally ready to run. I held my thumb high and laughed out loud into the blank space. I can actually move!