His name is Billy the and is made using LEGO parts.
It does with remarkable accuracy, which is the result of combining a accurate localization system and a motion control algorithm.
They are used to hold and control the height of the brush and even apply different amounts of pressure if needed.
He is about 25 cm tall and its trunk hosts a small (LEGO) microcomputer that is in charge of controlling him.
He can also apply different amounts of pressure to make thicker or thiner lines.
He has infrared sensors in his eyes that are used to communicate simple commands such as when to begin drawing. His mouth is a gyroscope that is used to track his orientation.
As any good artist, he signs his art when he finishes drawing.
Billy drawing Olaf
Most of the code used for this work has been open sourced
This website explains basic and advanced control an localization concepts used for this work