You can now ask your arm to hold a drawing pen by simply opening the claw, inserting a pen, and closing the claw. You'll probably want to use some sort of marker or other drawing device with a wide tip and lots of color. The following is the arm holding the pen:
If you adjust the servo that moves the entire arm up and down, you can make the pen touch the paper, as follows:
Finally, if you move the servo that turns the base, you can draw your first curved line, similar to the following image:
This is wonderful, but ...