diff --git a/misc/printBox.ml b/misc/printBox.ml
index b837ee92..8983894a 100644
--- a/misc/printBox.ml
+++ b/misc/printBox.ml
@@ -32,6 +32,7 @@ let origin = {x=0; y=0;}
 
 let _move pos x y = {x=pos.x + x; y=pos.y + y}
 let _add pos1 pos2 = _move pos1 pos2.x pos2.y
+let _minus pos1 pos2 = _move pos1 (- pos2.x) (- pos2.y)
 let _move_x pos x = _move pos x 0
 let _move_y pos y = _move pos 0 y
 
@@ -146,14 +147,13 @@ let rec _lines s i k = match _find s '\n' i with
 
 module Box = struct
   type grid_shape =
-    | GridBase
-    | GridFramed
+    | GridNone
+    | GridBars
 
   type 'a shape =
-    | Line of string
-    | Text of string list  (* in a box *)
+    | Text of string list  (* list of lines *)
     | Frame of 'a
-    | Pad of int * 'a
+    | Pad of position * 'a (* vertical and horizontal padding *)
     | Grid of grid_shape * 'a array array
 
   type t = {
@@ -174,6 +174,9 @@ module Box = struct
     if Array.length m = 0 then {x=0;y=0}
     else {y=Array.length m; x=Array.length m.(0); }
 
+  let _map_matrix f m =
+    Array.map (Array.map f) m
+
   (* height of a line composed of boxes *)
   let _height_line a =
     _array_foldi
@@ -193,27 +196,28 @@ module Box = struct
   (* from a matrix [m] (line,column), return two arrays [lines] and [columns],
     with [col.(i)] being the start offset of column [i] and
     [lines.(j)] being the start offset of line [j].
-    Those arrays have one more slot to indicate the end position. *)
-  let _size_matrix m =
+    Those arrays have one more slot to indicate the end position.
+    @param bars if true, leave space for bars between lines/columns *)
+  let _size_matrix ~bars m =
     let dim = _dim_matrix m in
+    (* +1 is for keeping room for the vertical/horizontal line/column *)
+    let additional_space = if bars then 1 else 0 in
     (* columns *)
     let columns = Array.make (dim.x + 1) 0 in
     for i = 0 to dim.x - 1 do
-      (* +1 is for keeping room for the vertical/horizontal line/column *)
-      columns.(i+1) <- columns.(i) + 1 + (_width_column m i)
+      columns.(i+1) <- columns.(i) + (_width_column m i) + additional_space
     done;
     (* lines *)
     let lines = Array.make (dim.y + 1) 0 in
     for j = 1 to dim.y do
-      lines.(j) <- lines.(j-1) + 1 + (_height_line m.(j-1))
+      lines.(j) <- lines.(j-1) + (_height_line m.(j-1)) + additional_space
     done;
     (* no trailing bars, adjust *)
-    columns.(dim.x) <- columns.(dim.x) - 1;
-    lines.(dim.y) <- lines.(dim.y) - 1;
+    columns.(dim.x) <- columns.(dim.x) - additional_space;
+    lines.(dim.y) <- lines.(dim.y) - additional_space;
     lines, columns
 
   let _size = function
-    | Line s -> { x=String.length s; y=1 }
     | Text l ->
         let width = List.fold_left
           (fun acc line -> max acc (String.length line)) 0 l
@@ -222,13 +226,16 @@ module Box = struct
     | Frame t ->
         let {x;y} = size t in
         { x=x+2; y=y+2; }
-    | Pad (n, b') -> 
-        assert (n>0);
+    | Pad (dim, b') -> 
         let {x;y} = size b' in
-        { x=x+2*n; y=y+2*n; }
-    | Grid (_,m) ->
+        { x=x+2*dim.x; y=y+2*dim.y; }
+    | Grid (style,m) ->
+        let bars = match style with
+          | GridBars -> true
+          | GridNone -> false
+        in
         let dim = _dim_matrix m in
-        let lines, columns = _size_matrix m in
+        let lines, columns = _size_matrix ~bars m in
         { y=lines.(dim.y); x=columns.(dim.x)}
 
   let _make shape =
@@ -237,7 +244,7 @@ end
 
 let line s =
   assert (_find s '\n' 0 = None);
-  Box._make (Box.Line s)
+  Box._make (Box.Text [s])
 
 let text s =
   let acc = ref [] in
@@ -255,32 +262,38 @@ let bool_ x = line (string_of_bool x)
 let frame b =
   Box._make (Box.Frame b)
 
-let pad' n b =
-  assert (n>=0);
-  if n=0 then b else Box._make (Box.Pad (n, b))
+let pad' ~col ~lines b =
+  assert (col >=0 || lines >= 0);
+  if col=0 && lines=0
+    then b
+    else Box._make (Box.Pad ({x=col;y=lines}, b))
 
-let pad b = pad' 1 b
+let pad b = pad' ~col:1 ~lines:1 b
 
-let grid ?(pad=false) ?(framed=true) m =
-  let b = Box._make (Box.Grid ((if framed then Box.GridFramed else Box.GridBase), m)) in
-  if pad then pad' 1 b else b
+let hpad col b = pad' ~col ~lines:0 b
+let vpad lines b = pad' ~col:0 ~lines b
 
-let init_grid ?pad ?framed ~line ~col f =
+let grid ?(pad=fun b->b) ?(bars=true) m =
+  let m = Box._map_matrix pad m in
+  Box._make (Box.Grid ((if bars then Box.GridBars else Box.GridNone), m))
+
+let init_grid ?bars ~line ~col f =
   let m = Array.init line (fun j-> Array.init col (fun i -> f ~line:j ~col:i)) in
-  grid ?pad ?framed m
+  grid ?bars m
 
-let vlist ?pad ?framed l =
+let vlist ?pad ?bars l =
   let a = Array.of_list l in
-  grid ?pad ?framed (Array.map (fun line -> [| line |]) a)
+  grid ?pad ?bars (Array.map (fun line -> [| line |]) a)
 
-let hlist ?pad ?framed l =
-  grid ?pad ?framed [| Array.of_list l |]
+let hlist ?pad ?bars l =
+  grid ?pad ?bars [| Array.of_list l |]
 
-let hlist_map ?pad ?framed f l = hlist ?pad ?framed (List.map f l)
-let vlist_map ?pad ?framed f l = vlist ?pad ?framed (List.map f l)
-let grid_map ?pad ?framed f m = grid ?pad ?framed (Array.map (Array.map f) m)
+let hlist_map ?bars f l = hlist ?bars (List.map f l)
+let vlist_map ?bars f l = vlist ?bars (List.map f l)
+let grid_map ?bars f m = grid ?bars (Array.map (Array.map f) m)
 
-let grid_text ?pad ?framed m = grid_map ?pad ?framed text m
+let grid_text ?(pad=fun x->x) ?bars m =
+  grid_map ?bars (fun x -> pad (text x)) m
 
 let transpose m =
   let dim = Box._dim_matrix m in
@@ -299,10 +312,10 @@ let _write_hline ~out pos n =
 
 (* render given box on the output, starting with upper left corner
     at the given position. [expected_size] is the size of the
-    available surrounding space *)
-let rec _render ?expected_size ~out b pos =
+    available surrounding space. [offset] is the offset of the box
+    w.r.t the surrounding box *)
+let rec _render ?(offset=origin) ?expected_size ~out b pos =
   match Box.shape b with
-    | Box.Line s -> Output.put_string out pos s
     | Box.Text l ->
         List.iteri
           (fun i line ->
@@ -319,12 +332,16 @@ let rec _render ?expected_size ~out b pos =
         _write_vline out (_move_y pos 1) y;
         _write_vline out (_move pos (x+1) 1) y;
         _render ~out b' (_move pos 1 1)
-    | Box.Pad (n, b') ->
+    | Box.Pad (dim, b') ->
         let expected_size = Box.size b in
-        _render ~expected_size ~out b' (_move pos n n)
-    | Box.Grid (grid_shape,m) ->
+        _render ~offset:(_add dim offset) ~expected_size ~out b' (_add pos dim)
+    | Box.Grid (style,m) ->
         let dim = Box._dim_matrix m in
-        let lines, columns = Box._size_matrix m in
+        let bars = match style with
+          | Box.GridNone -> false
+          | Box.GridBars -> true
+        in
+        let lines, columns = Box._size_matrix ~bars m in
 
         (* write boxes *)
         for j = 0 to dim.y - 1 do
@@ -344,14 +361,14 @@ let rec _render ?expected_size ~out b pos =
         in
 
         (* write frame if needed *)
-        begin match grid_shape with
-        | Box.GridBase -> ()
-        | Box.GridFramed ->
+        begin match style with
+        | Box.GridNone -> ()
+        | Box.GridBars ->
           for j=1 to dim.y - 1 do
-            _write_hline ~out (_move_y pos (lines.(j)-1)) len_hlines
+            _write_hline ~out (_move pos (-offset.x) (lines.(j)-1)) len_hlines
           done;
           for i=1 to dim.x - 1 do
-            _write_vline ~out (_move_x pos (columns.(i)-1)) len_vlines
+            _write_vline ~out (_move pos (columns.(i)-1) (-offset.y)) len_vlines
           done;
           for j=1 to dim.y - 1 do
             for i=1 to dim.x - 1 do
diff --git a/misc/printBox.mli b/misc/printBox.mli
index 4fd145e5..966f745c 100644
--- a/misc/printBox.mli
+++ b/misc/printBox.mli
@@ -124,37 +124,45 @@ val frame : Box.t -> Box.t
 val pad : Box.t -> Box.t
 (** Pad the given box with some free space *)
 
-val pad' : int -> Box.t -> Box.t
-(** Pad with the given number of free cells *)
+val pad' : col:int -> lines:int -> Box.t -> Box.t
+(** Pad with the given number of free cells for lines and columns *)
 
-val grid : ?pad:bool -> ?framed:bool -> Box.t array array -> Box.t
+val vpad : int -> Box.t -> Box.t
+(** Pad vertically *)
+
+val hpad : int -> Box.t -> Box.t
+(** Pad horizontally *)
+
+val grid : ?pad:(Box.t -> Box.t) -> ?bars:bool ->
+           Box.t array array -> Box.t
 (** Grid of boxes (no frame between boxes). The matrix is indexed
     with lines first, then columns. The array must be a proper matrix,
     that is, all lines must have the same number of columns!
     @param framed if [true], each item of the grid will be framed.
       default value is [true] *)
 
-val grid_text : ?pad:bool -> ?framed:bool -> string array array -> Box.t
+val grid_text : ?pad:(Box.t -> Box.t) -> ?bars:bool ->
+                string array array -> Box.t
 (** Same as {!grid}, but wraps every cell into a {!text} box *)
 
 val transpose : 'a array array -> 'a array array
 (** Transpose a matrix *)
 
-val init_grid : ?pad:bool -> ?framed:bool ->
+val init_grid : ?bars:bool ->
                 line:int -> col:int -> (line:int -> col:int -> Box.t) -> Box.t
 (** Same as {!grid} but takes the matrix as a function *)
 
-val vlist : ?pad:bool -> ?framed:bool -> Box.t list -> Box.t
+val vlist : ?pad:(Box.t -> Box.t) -> ?bars:bool -> Box.t list -> Box.t
 (** Vertical list of boxes *)
 
-val hlist : ?pad:bool -> ?framed:bool -> Box.t list -> Box.t
+val hlist : ?pad:(Box.t -> Box.t) -> ?bars:bool -> Box.t list -> Box.t
 (** Horizontal list of boxes *)
 
-val grid_map : ?pad:bool -> ?framed:bool -> ('a -> Box.t) -> 'a array array -> Box.t
+val grid_map : ?bars:bool -> ('a -> Box.t) -> 'a array array -> Box.t
 
-val vlist_map : ?pad:bool -> ?framed:bool -> ('a -> Box.t) -> 'a list -> Box.t
+val vlist_map : ?bars:bool -> ('a -> Box.t) -> 'a list -> Box.t
 
-val hlist_map : ?pad:bool -> ?framed:bool -> ('a -> Box.t) -> 'a list -> Box.t
+val hlist_map : ?bars:bool -> ('a -> Box.t) -> 'a list -> Box.t
 
 val render : Output.t -> Box.t -> unit