anchor.diff:          let pixelSize = 30.0
   
           let planeSize = 10.0
  -        let texelSize = 5.0
  +        let texelSize = 16.0
   
           [<AutoOpen>]
           module Tools =
  
positive.code: 
                  let i0 = 0.5 * (t1 + t3)
                  let i1 = 0.5 * (t0 + t2)
                  //return { innerLevel = [|1.0; 1.0|]; outerLevel = [| 1.0; 1.0; 1.0; 1.0 |]} 
                  return { innerLevel = [|i0; i1|]; outerLevel = [| t0; t1; t2; t3 |]}  
              }
  
          let pgmTessEval (m : Patch4<Vertex>) =
              tessEval {
                  let c = m.TessCoord.XY
  
                  let wp = interpolate4 c m.P0.wp m.P1.wp m.P2.wp m.P3.wp
                  let tc, dtx, dty = gradient2 c m.P0.tc m.P1.tc m.P2.tc m.P3.tc
  
  
                  let h = heightSampler.SampleGrad(tc, dtx, dty).X * 1.5
                  let wp = wp + V4d(0.0, 0.0, h, 0.0)
  
  
  
negative.code: 
  
              let interpolate2 (c : V2d) (p0 : V2d) (p1 : V2d) (p2 : V2d) (p3 : V2d) =
                  let x = c.X //clamp 0.0 1.0 c.X
                  let y = c.Y //clamp 0.0 1.0 c.Y
                  let a = p0 * (1.0 - x) + p1 * x
                  let b = p2 * (1.0 - x) + p3 * x
                  a * (1.0 - y) + b * y
  
              let interpolate3 (c : V2d) (p0 : V3d) (p1 : V3d) (p2 : V3d) (p3 : V3d) =
                  let x = c.X //clamp 0.0 1.0 c.X
                  let y = c.Y //clamp 0.0 1.0 c.Y
                  let a = p0 * (1.0 - x) + p1 * x
                  let b = p2 * (1.0 - x) + p3 * x
                  a * (1.0 - y) + b * y
  
              let interpolate4 (c : V2d) (p0 : V4d) (p1 : V4d) (p2 : V4d) (p3 : V4d) =
                  let x = c.X //clamp 0.0 1.0 c.X
                  let y = c.Y //clamp 0.0 1.0 c.Y
                  let a = p0 * (1.0 - x) + p1 * x
                  let b = p2 * (1.0 - x) + p3 * x
                  a * (1.0 - y) + b * y
  