Before the robot arm can accurately perform a task, such as carve up a mold placed in front of it, it needs to understand where that object is located in three dimensional space in relation to itself. A previous blog post showed how it used a piezoelectric button to tap on a base surface to determine the surface's orientation and position in 3-space. This video shows how it now understands the location of the base surface sufficiently to keep a pen lightly drawing across the surface.