This construction kit challenges you to not only Build Genius, but also build a fully functional VEX Orbit at the same time. One crank of the dial is equal to one calendar day here on Earth. You can even learn how to set the Orbit kit to correspond with today's date! By turning the rotation knob, you cause a sequence of gears to work together to revolve the Earth and Moon around the Sun! Each crank is equal to one calendar day here on Earth!