anchor.diff:          LastTime: float
           UpdateTime: float
           UpdateAccumulator: float
  -        RenderAccumulator: float
           RenderInterval: float }
   
       let start (state: 'T) (update: float -> float -> 'T -> 'T) (render: float -> 'T -> 'T -> unit) =
  
positive.code:               LastTime = 0.
                UpdateTime = 0.
                UpdateAccumulator = 0.
                RenderAccumulator = 0.
                RenderInterval = 0. }
  
  [<EntryPoint>]
  
negative.code:                     gl
  
              let processRender gl =
                  render (gl.UpdateAccumulator / targetUpdateInterval) gl.PreviousState gl.State                
  
                  { gl with 
                      LastTime = currentTime }
                           
              { gl with UpdateAccumulator = updateAcc }
              |> processUpdate
              |> processRender
              |> loop
  