This lesson focuses on the subjects of perspective and vanishing points.
The video shows a very quick sketch of a room (which is made up) that demonstrates the two point linear perspective, which is the most commonly used by artists. Notice the two vanishing points on the horizon. In this case both of the vanishing points are inside the sheet of paper. This is not always the case. When drawing, the vanishing points will always be on the horizon. The horizon will always be on the level of the eyes of the observer. Notice how on the sketch all the parallel lines converge to the same vanishing point.
Drawing interior spaces is a very good way to understand perspective. For practice, try drawing the rooms inside your house.
Via Cristina Gevorgyan