Trying to simulate drawing styles of art giants is a great way to learn a lot about technique and gain insight into the mastery of the craft.
Leonardo da Vinci, study of a horse (pencil)
Leonardo da Vinci, Vitruvian man (pencil)
Leonardo da Vinci, charicature (pencil)
Michelangelo, Seated male nude (colored charcoal)
Michelangelo, Madonna and child (pencil)
Edgar Degas, ballerinas (charcoal)