The stairway at the Apple store

I had to go to the Genius Bar to get my old Macbook Pro wiped clean before it could be sent to recycling. It was so old (I bought it in 2010, and only replaced it recently) that my assigned Genius had to call in an even more senior Genius to solve the erase problem. On my way out, I captured this glimpse of the transparent stairway leading down from the third floor to the first.