Explanation taken from their website:
“The Tagtool is a performative visual instrument used on stage and on the street. It serves as a VJ tool, a creative video game, or an intuitive way of creating animation.
The system is operated collaboratively by an artist drawing the pictures and an animator adding movement to the artwork with a gamepad. The design achieves virtually unlimited artistic complexity with a simple set of controls, which can be mastered even by children.”
You should definitely check their website for more pictures, projects and informations about the Tagtool.