A particle on a circle through points that have been marked 1, 2, 3, 4, 5 (in a clockwise order). The particle starts at point 1. At each step, it has probability 0.5 of moving one point clockwise (1 follows 5) and 0.5 of moving one point counterclockwise. Let $X_n$ (n$\leq 0$) denotes its location on the circle after step n. $\{X_n\}$ is a Markov chain