You have drawn a box in perspective and you can't see through a box. So erase the horizon line where it passes behind the box. Do not erase so hard that you hurt the paper.
We need some marks to help us make the roof and door. So lay your ruler as if you were going to make the first angular line over again.
Make three marks on the line at two (2) centimeters, three (3) centimeters and put the final mark two millimeters before the four- (4) centimeter mark. The far away half of the door will be a little shorter than the close half of the door.
THE ART POEM
