anchor.diff:          let fails = extractFailures model 
           Map.toSeq fails 
           |> Seq.map (fun (name,term) -> printZTermGrass model.SharedVars name term) 
  -        |> vsep
  +        |> (fun x -> (VSep (x,VSkip))) 
   
       /// Print a Grasshopper error (not implemented yet)
       let printGrassError e = failwith "not implemented yet" 
  
positive.code:         // TODO @(septract) print command properly 
          let cmdprint = zterm.SymBool.Cmd 
                         |> (Core.Expr.Pretty.printBoolExpr (printSymGrass printMarkedVarGrass))
          vsep [ String "procedure" <+> String name <+> (varprint |> parened) 
                 // String "requires" 
                 //(printConstrGrass (String "requires ") zterm.SymBool.WPre) 
                 //(printConstrGrass (String "ensures  ") zterm.SymBool.Goal) 
                 String "requires" 
                 Indent wpreprint 
                 String "ensures" 
                 Indent goalprint
                 cmdprint 
                      |> ssurround "/*" "*/" 
                      |> Indent |> braced 
               ]  
  
      /// Print all the Grasshopper queries that haven't been eliminated by Z3.      
  
negative.code: 
      /// Get the set of accessed variables. 
      let findVarsGrass (zterm : Backends.Z3.Types.ZTerm) : seq<MarkedVar> = 
          BAnd [zterm.SymBool.WPre; zterm.SymBool.Goal; zterm.SymBool.Cmd] 
          |> findMarkedVars (tliftToBoolSrc (tliftToExprDest collectSymMarkedVars)) 
          |> lift (Set.map valueOf >> Set.toSeq) 
          |> returnOrFail
  
      /// Print a single Grasshopper query from a ZTerm 
      let printZTermGrass (svars : VarMap) 
  