Or presumably you could go one further and solve for the fundamental matrix which gives total probabilities (given unlimited steps) of ending at either end of t

Or presumably you could go one further and solve for the fundamental matrix which gives total probabilities (given unlimited steps) of ending at either end of the plank ('absorbing' states which you don't come back from). see: http://www.math.dartmouth.edu/archive/m20x06/public_html/Lecture14.pdf http://www.math.dartmouth.edu/archive/m20x06/public_html/Lec...