Second (Floor) ========= ==========
First (Floor) ========== ============
I have the 1st floor if I walk and fall into a hole, I die. However, I have a 2nd floor, which I can jump on it, ie 1st floor to the 2nd floor, I want the 2nd floor becomes the last floor. If eventually, I dropped it, I would not return to the previous floor, I will die.
And so to all other floors.