A motion simulator or motion platform is a mechanism that creates the feelings of being in a real motion environment. In a simulator, the movement is synchronised with a visual display of the outside world (OTW) scene. Motion platforms can provide movement in all of the six degrees of freedom (DOF) that can be experienced by an object that is free to move, such as an aircraft or spacecraft:. These are the three rotational degrees of freedom (roll, pitch, yaw) and three translational or linear degrees of freedom (surge, heave, sway). Types Motion simulators can be classified according to whether the occupant is controlling the vehicle(such as in a Flight Simulator for training pilots), or whether the occupant is a passive rider, such as in a simulator ride or motion theater. Examples of occupant-controlled motion simulators are flight simulators, driving simulators, and hydraulic arcade cabinets for racing games and other arcade video games. Other occupant-controlled vehicle simulation games simulate the control of boats, motorcycles, rollercoasters, military vehicles, ATVs, or spacecraft, among other craft types. Examples of passive ride simulators are theme park rides where an entire theater system, with a projection screen sit in front of riders. The motion simulator base can also be portable as with the enhanced motion vehicle. See Simulator ride and the Ride simulator section of this article for more details on passive motion simulators. Motion platforms for aircraft simulators are at the high end, plus some of the more expensive amusement park rides that use a simulator-type motion base; arcade amusement devices are in the middle, and motion platforms for home use are low-cost but not as capable of the higher-level devices. Many motion platforms are used in flight simulators used to train pilots. History of motion platforms One of the first motion platforms, the Sanders Teacher, was created in 1910. This was a model aircraft connected to the ground by a universal joint. When wind was present, the pilot in training was able to use the aircraft's control surfaces to move the model in the three rotational degrees of freedom pitch, roll and yaw. In 1929 a significant advance in motion platform technology was made with the patent by Edwin Link for what became known as the "Link Trainer". This used the pilot's control stick and rudder controls to control organ-type bellows under the simulator cockpit. The bellows could inflate or deflate, giving movement