Line
Two-point perspective is when the planes of the object are not parallel ("skewed") in relation to the picture plane. As with one-point perspective, the viewer's eye 
level is established by drawing a horizon line. Two vanishing points are located on either side of the object, most often placed beyond the borders of the picture space. The solid's closest corner is drawn and the receding planes established by following the orthogonals from the ends of this edge to the vanishing points.  In two-point perspective all lines except the verticals, which remain parallel, can be traced back to these points.