anchor.diff:  
   do_flight_control(Entity) ->
   	Physical = dict:fetch(physical, Entity#entity.state),
  -	Orientation = dict:fetch(orientation, Physical),
  -	PositionVelAbs = dict:fetch(linear_velocity, Physical),
  -	AngularVelAbs = dict:fetch(angular_velocity, Physical),
  +	Orientation = pre_physics_rk4:get_prop(orientation, Physical),
  +	PositionVelAbs = pre_physics_rk4:get_prop(linear_velocity, Physical),
  +	AngularVelAbs = pre_physics_rk4:get_prop(angular_velocity, Physical),
   
   	ShipState = dict:fetch(ship, Entity#entity.state),
   	{TX, TY, TZ} = dict:fetch(target_linear_velocity, ShipState),
  
positive.code: 	},
  
  	% Update physical state
  	NewPhysical1 = dict:store(force_relative, Force, Physical),
  	NewPhysical2 = dict:store(torque_relatice, Torque, NewPhysical1),
  
  	% Update entity state
  	Entity#entity{
  		state = dict:store(physical, NewPhysical2, Entity#entity.state)
  	}.
  
  
  
negative.code: 	% -------------------------------------------------------------------------
  
  	% Set up our initial state
  	State1 = Entity#entity.state,
  	State2 = dict:store(ship, Ship, State1),
  
  	Entity#entity{
  		state = State2
  	}.
  
  