Contour drawing is a continuous line drawing of the outer edge of a subject. The purpose of a contour drawing is to practice looking slowly and carefully at the details of your subject's outer edge, timing your eye with the movement of your hand. It is done slowly without lifting your pencil or pen.
A blind contour means you do not "peek" by looking at your paper to check where your pencil is on your paper.
All lines converge to vanishing points on right or left
Personal Values by Rene Magritte,
Persistence of Memory by Salvador Dali, 1931
Georgia O'Keeffe
Lillian Thomas Burwell