anchor.diff:  [<DiamondProperty>]
   let ``All rows must have a symmetric contour`` (letter : char) =
       let actual = make letter
  -
       let rows = split actual
       rows |> Array.forall (fun r -> (leadingSpaces r) = (trailingSpaces r))
   
   [<DiamondProperty>]
   let ``Top of figure has correct letters in correct order`` (letter : char) =
       let actual = make letter
  -    printfn "%s" actual
  -
       let expected = ['A' .. letter]
       let rows = split actual
       
  
positive.code: 
  [<DiamondProperty>]
  let ``Dimaond is non empty`` (letter : char) =
      // printfn "%c" letter
      let actual = make letter
      not (String.IsNullOrWhiteSpace actual)
  
  
negative.code: let ``First row contains 'A'`` (letter : char) =
      let actual = make letter
      let rows = split actual
      rows |> Seq.head |> trim = "A"
  
  let leadingSpaces (x : string) =
  