In this demonstration, you can adjust the length of the vector by dragging its endpoint. You can drag the middle point to change its direction, and you can drag its initial point to change its position. You can also change the shape of the quadrilateral by dragging its vertices.
Try all three points on the vector. Notice how the quadrilateral is translated depending on the length and direction of the vector.
Move the vector so that it connects each "before" point on the quadrilateral to its "after" point. Notice that the position of the vector doesn't affect how the quadrilateral is translated.