"Microchip engineers may not seem like creative types, but they've been quietly using silicon as a canvas for decades. When magnified 1,000 to 5,000 times, some semiconductors reveal tiny works of art etched there by their makers." - START, etchings, Todd Jatras, December 2005.
Chipworks is an engineering firm that has collected these disappearing little art forms and put them in a gallery on their web site. There's everything from animals to fictional characters to messages. Ghost in the machine?
I remember back in the 80's typing out an image of the robot from "LOST IN SPACE" in the comment lines of my code (pre emoticon days).
People just can't help but be creative.