Vex Robotics Hexcalator Ball MachineDetails: This construction kit challenges you to not only Build Genius, but does so while constructing a roller coaster style ball machine at the same time. Once built, watch as the gears turn, the axles twist and the balls roll as you turn the knob by hand or attach a motor kit to add power to this machine! HEXBUG believes in using the fun of robotic toys to teach kids important STEM principles through hands on learning. The VEX Robotics Hexcalator