anchor.diff:  
   
   open Fable.Core
  +open Fable.Core.JsInterop
   open Fable.Import.Browser
   
   type Complex = { r : double; i : double }
  
positive.code: 
  let maxIter = 255
  
  let height = 512
  let width = 512
  
  let minX = -2.1
  let maxX = 0.5
  let minY = -1.4
  let maxY = 1.4
  
  let iteratePoint (s : Complex) (p : Complex) : Complex =
      { r = s.r + p.r*p.r - p.i*p.i; i = s.i + 2.0 * p.i * p.r }
  
negative.code:       i <- i + 1
      i
  
  let getCoord (x : int, y : int) : Complex =
      let p = { r = float x * (maxX - minX) / float width + minX
              ; i = float y * (maxY - minY) / float height + minY }
      p
  
  let getCoordColor (x : int, y : int) : Color =
      let p = getCoord (x, y)
      let i = getIterationCount p
      { r = 255/(i%5); g = 255/(i%3); b = 255/(i%7); a = 255}
  
  let showSet() =
      let ctx = document.getElementsByTagName_canvas().[0].getContext_2d()
  