Drawing is one of the oldest human practices, with evidence of this art form from over 30,000 years ago; in the early days of man, drawing was used as a form of communication before the development of the written language, eventually evolving into an art form. Styles, techniques and materials used for drawing have changed and advanced throughout this extensive period. Since prehistoric times up until the modern day, various surfaces have been used to apply materials such as pencil and ink to; traditional surfaces include paper and canvas. Important examples of drawing from Renaissance artists such as Leonardo da Vinci and Raphael still survive today, with perhaps the most infamous being the former's 'Vitruvian Man'. Whilst 20th century artist Picasso is famous for his unmistakeable paitings, the surrealist produced over 12,000 drawings during his lifetime. In 2013, a pencil drawing from Picasso entitled 'Buste de Femme' sold for $746,500 at auction.