A figure drawing is a drawing of the human form in any of its various shapes and postures using any of the drawing media. The term can also refer to the act of producing such a drawing. The degree of representation may be from highly detailed, anatomically correct renderings to loose and expressive sketches. A "life drawing" is a drawing of the human figure from observation of a live model. A figure drawing may be a composed work of art or a figure study done in preparation for a more finished work such as a painting. Figure drawing is arguably the most difficult subject an artist commonly encounters, and entire courses are dedicated to the subject. The human figure is one of the most enduring themes in the visual arts, and the human figure can be the basis of portraiture, illustration, sculpture, medical illustration, and other fields.