anchor.diff:  
                   let markTime = (float swMark.ElapsedTicks / float Stopwatch.Frequency)
                   let evalTime = (float swEval.ElapsedTicks / float Stopwatch.Frequency)
  -                Log.stop " MarkTime=%.2fs EvalTime=%.2fs" markTime evalTime
  +                //Log.stop " MarkTime=%.2fs EvalTime=%.2fs" markTime evalTime
   
                   totalMarkTime <- totalMarkTime + markTime
                   totalEvalTime <- totalEvalTime + evalTime
  
positive.code:                         let subCnt = rnd.Gaussian(0.0, stdWidth)
                          let refine = (abs subCnt) |> int
                          for r in 0..refine do
                              //let n = l |> Mod.map (fun x -> x * 2)
                              let xx = Mod.init Trafo3d.Identity
                              let n = Mod.map2 (fun a b -> a * b) xx l
                              nextLevel <- nextLevel @ [n]
                              nodeCount <- nodeCount + 1 
                          ()
  
negative.code: 
          let mutable garbage = [ ]
  
          for j in 0..0 do // loop used for repeated testing in standalone executable
              let mutable totalMarkTime = 0.0
              let mutable totalEvalTime = 0.0
              let iter = 10
              for k in 1..iter do
                  //let root = Mod.init Trafo3d.Identity
                  let root = Mod.init 10
                  let mutable leafs = [ root :> IMod<_> ]
                  let rnd = RandomSystem(1)
  
                  // configuration 1: average of 2-3 outputs, less depth
                  let depth = int (10.0 * pow 1.1 (float k))
                  let stdWidth = 1.2
  
                  // configuration 2: average 1-2 outputs, deeper tree
                  //let depth = int (10.0 * pow 1.5 (float k))
                  //let stdWidth = 0.3
  
                  let mutable nodeCount = 0
                  //Log.startTimed "Create Tree: Depth=%d StdWidth=%.2f" depth stdWidth
                  for i in 1..depth do
  