It is always fun to print some text or drawings onto a spherical object. And it was easier to build this time as the new Lego Mindstorms NXT motors are easy to control.
The robot can draw the world from a white ball using zigzag lines to label the continents as well as the oceans. Two motors were being used for tilting and rotating the ball while the third motor has a dual function such as to select the desired color to use with and it lifts the pen when not in use.
There is a touch sensor attached on the frame to detect the initial position of the three felt tip pens.