I've posted on the Ten Ox Herding Pictures, or the Ten Bulls, before. This website crossed my path, so I thought I'd post again. If you click on the title of this post, you'll be directed to the Ten Ox Herding pictures, and their explanations.
The 10 Bulls depict a journey, the goal of which is enlightenment. The bull is the eternal principle of life; one's true nature.
In the 12th century the Chinese master Kakuan drew the 10 bulls, basing them on earlier Taoist drawings. The earlier drawings had only 8 bulls, with the eighth representing the final stage of enlightenment. Kakuan went beyond this, illustrating that the moment of enlightenment is merely a beginning.
These bulls were drawn by the Kyoto woodblock artist Tomikichiro Tokuriki, and published in Zen Flesh, Zen Bones by Paul Reps.