A look at Leonardo Da Vinci's equestrian drawings...
While studying master drawings by Da Vinci, we can see traces of his process. These sketches of many-legged horses do not reveal mistakes. It took all of these repeated drawings of the legs to find their perfect placement. Each was a necessary step.
The effect of leaving these sketches in the drawing is of motion, particularly in this one (below) of a rearing horse, where he captured its position at different moments:
There is evidence of decision making in many of Da Vinci's drawings which make them interesting to study, such as this one (below) where he determines the position of the rider's head in order to achieve the most satisfying composition:
These drawings offer great examples of how artists use drawing as a medium in which to think.