anchor.diff:  
         let fromFileColumnsWithOffsetAndSize<'a when 'a : unmanaged and 'a : (new : unit -> 'a) and 'a : struct and 'a :> ValueType> (offset : int) (size : int) (fileName : string) =
           let stream = File.OpenRead fileName
  -        loadFromStreamColumnsWithOffset<'a> offset size stream
  -
  -
  -
  -
  +        loadFromStreamColumnsWithOffset<'a> offset size stream
positive.code:         )
          Array.Resize(&arr, cnt)
          arr
  
      module Offset = 
  
  
negative.code: 
      let inline isNan (v : V3f) = 
          v.X.IsNaN() || v.Y.IsNaN() || v.Z.IsNaN()
  
      let inline triangleIsNan (t:Triangle3d) =
          t.P0.AnyNaN || t.P1.AnyNaN || t.P2.AnyNaN
  
      let createIndex (vi : Matrix<V3f>) =
          let dx = vi.Info.DX
  