anchor.diff:                              for v in q1.EdgeLines do
                                   let mutable t = nan
                                   match u.Ray2d.Intersects(v, &t) with
  -                                    | true when t > 0.1 && t < 0.9 -> yield true
  +                                    | true when t > 0.001 && t < 0.999 -> yield true
                                       | _ -> ()
                       }
                   realIntersections |> Seq.isEmpty |> not
  
positive.code:             run (Array.toList p.outline)
  
              // merge the interior polygons (respecting holes)
              let innerPoints = innerPoints |> Seq.map (CSharpList.toArray >> Polygon2d) |> Seq.toList
  
              let mergePolys(a : Polygon2d) (b : Polygon2d) =
                  
                  let distances =
                      seq {
                          for i in 0..a.PointCount-1 do
  
negative.code:                         let p2Inside = p2.PosLeftOfLineValue(p0, p3) > 0.0
  
                          let overlapping = allSplines |> Seq.exists (overlap q)
                          if overlapping then
  
                              let m0 = 0.5 * (p1 + p0)
                              let m1 = 0.5 * (p1 + p2)
  