finding a steady state matrix

A security guard is employed to patrol a shopping complex. The guard

is instructed to wait 10 minutes at each corner (numbered 1 to 4.)

After 10 minutes, the guard must either stay where he is or move to

one of the adjacent corners. Movements should be at random so that the

chances of remaining or moving to each adjoining corner are the same.

What is the steady-state matrix for the likelihood of the guard's being

at each of the corners?

Other information given:

the steady state vector is defined as **s = lim (n -> infinity) of x^n.**

Since s is independent from initial conditions, it must be unchanged when

transformed by P i.e sP = s.

If someone could briefly explain this as well that would be great.

Thanks in Advance.