Snap (and Scratch, from which Snap was derived) borrowed the pen feature from another older language called “Logo”. And Logo contained a single sprite – a triangular shape called “Turtle”! This Turtle had a pen attached to it. And so, as it followed instructions and was moved around on the screen, it drew lines. Hence, the entire field of drawing shapes in Logo came to be called “Turtle Programming”. There is even a field of geometry called “Turtle Geometry”. Modern languages, such as Python, have the aptly-named “Turtle” libraries that implement the drawing feature of Logo. Snap, being a descendant of Logo, includes the Pen. Every sprite in Snap has a pen attached to it (just like the Turtle did in Logo). When the pen is put down (using the “pen down” command), the sprite starts drawing on the screen as it moves around. Since our focus in this book is entirely on “Pen Art” we have no use for the hundreds of costumes provided by the Snap library. We will use the original triangle-shaped costume called “Turtle” in all our Snap programs in this book.