I developed a drawing machine on the basis of a robot kit.
Two servos with step motors simulate shoulder and elbow joint. the machine illuminates the drawing surface with infrared light, can thus detect light and dark areas on the drawing paper with appropriate sensors, and adjusts its movement accordingly.
The robot responds, so to speak, to what it has drawn so far.
The algorythm written in basic also contains a random function that prevents the drawing of exact straight lines or arcs by making the drawing arm tremble. The results thus look somewhat like human hand drawings.
the drawing machine at work in an early test phase: