Vex robotics 406 4207 screw lift ball machine by hexbug vex 406 4207 p the vex reg robotics screw lift ball machine by hexbug reg teaches important scientific principals such as kinematics linkages and reciprocal motion p p inspired by the original design of one of the greatest scientific minds of ancient greece this modern machine puts a fresh twist on the archimedes screw from the 3rd century b c this system is time tested and still used by many industries to move small objects or