(a) A good example of a simple random walk with two reflecting barriers is the movement of an elevator in a 10 storey building. Once the elevator reaches the ground floor, it will have a 100% probability of going up, and when it reaches the 10th floor, it will have a 100% probability of going down. The elevator goes up and down at discrete intervals. Reflection at the barriers is represents the points when the elevator is at the ground and the 10th floors.
(b) (i) 1.