The displacement from point B to point A is:

- The x displacement: 2-7 = -5
- The y displacement: 1-3 = -2

So the column matrix representing the displacement is:

e = (-5, -2)^{T}

When the points are visited in the opposite order, the displacement vector points in the opposite direction. In the column matrix each element is -1 times the old value.

The displacement from A to B is different from the displacement from B to A.
Think of displacement as "directions on how to walk from one point
to another."
So, if you are standing on point A and wish to get to point B,
the displacement (3, 1)^{T} says "walk 3 units in the positive X direction,
then walk 1 unit in the positive Y direction."

Of course, to get from point B to point A you need different directions:
the displacement (-3, -1)^{T} says "walk 3 units in the
*negative* X direction,
then walk 1 unit in the *negative* Y direction,"
which puts you back on point A.

The displacement from point **Start** to point **Finish** ==

(Finish x - Start x , Finish y - Start y)^{T}