anchor.diff:        forests = HashSet<Location>()
         cameFrom = Dictionary<Location, Location>()
         costSoFar = Dictionary<Location, int>()
  +      path = []
       }
   
     // Make "diagram 4" from main article
  
positive.code:       else if (pointer.y = y - 1)              then Console.Write("↑ ")
        else                                          Console.Write("* "))
      Console.WriteLine())
  
  "Example test" &&& fun ctx ->
    let graph =
  
negative.code:     forests : HashSet<Location>
      cameFrom : Dictionary<Location, Location>
      costSoFar : Dictionary<Location, int>
      path : Location list
    }
  
  let inBounds grid location =
  