Nothing but anatomy. Seriously.
In The High School of Art and Design, I've took a two-year course of Medical Illustration. Now, I've gotten better with it than ever. I draw body parts, muscles, and organs of a human. Check 'em out. They're Beautiful.

Arm & Back muscle (medium: black pen)

Leg Muscle (medium: black pen)

Arm Muscle in Color (mediums: black pen, red & bue marker)

Exterior of Back muscle (medium: black pen, red & blue marker)

Interior of Back muscle (medium: black pen, blue marker)

The Heart (2004)

Asthma in the Lungs (2004)

Leg Muscle #2 (medium: black pen, pink marker)

Pink Eye Project (2004)

Neck Muscle Sketch #1 (medium: blue pen, black pen)

Neck Muscle #2 (medium: black pen)

Neck and Head Muscles (medium: pencil)

Thigh Muscle (medium: pencil)

Leg Muscle (Pencil)

Want learn more anatomy? Try drawing weapons from Heavy Metal comic books.

Cesarean Section Project (Sexual Reproduction Project topic)