diff --git a/cpdfchop.ml b/cpdfchop.ml
index 40a2f3a..fa966fb 100644
--- a/cpdfchop.ml
+++ b/cpdfchop.ml
@@ -4,6 +4,7 @@ open Cpdferror
 (* Chop a single page into pieces. We prefer the cropbox when available. We set
    mediabox only, and delete any other boxes. We delete /Annots, since
    duplicate annotations are not allowed. *)
+
 let get_box pdf page =
   match Pdf.lookup_direct pdf "/CropBox" page.Pdfpage.rest with
   | Some r -> Pdf.parse_rectangle pdf r
@@ -14,28 +15,37 @@ let erase_boxes d =
     f (f (f (f (f d "/CropBox") "/BleedBox") "/TrimBox") "/ArtBox") "/Annots"
 
 let make_pages x y columns btt rtl w h ps move_page =
-  for ty = y - 1 downto 0 do for tx = 0 to x - 1 do
-    ps =| move_page (w *. float_of_int tx) (h *. float_of_int ty)
-  done done
+  if columns then
+    let column tx =
+      if btt then
+        for ty = 0 to y - 1 do ps =| move_page (w *. float_of_int tx) (h *. float_of_int ty) done
+      else
+        for ty = y - 1 downto 0 do ps =| move_page (w *. float_of_int tx) (h *. float_of_int ty) done
+    in
+      if rtl then for tx = x - 1 downto 0 do column tx done else for tx = 0 to x - 1 do column tx done
+  else
+    let row ty =
+      if rtl then
+        for tx = x - 1 downto 0 do ps =| move_page (w *. float_of_int tx) (h *. float_of_int ty) done
+      else
+        for tx = 0 to x - 1 do ps =| move_page (w *. float_of_int tx) (h *. float_of_int ty) done
+    in
+      if btt then for ty = 0 to y - 1 do row ty done else for ty = y - 1 downto 0 do row ty done
 
 let chop_boxes pdf x y columns btt rtl p =
-  if x < 1 || y < 1 then Cpdferror.error "chop_boxes bad specification" else
+  if x < 1 || y < 1 then error "chop_boxes bad specification" else
     let move_page mx my p w h dx dy =
-      (*Printf.printf "move_page by %f %f\n" dx dy;*)
       let nminx, nminy, nmaxx, nmaxy = (mx +. dx, my +. dy, mx +. w +. dx, my +. h +. dy) in
-        (*Printf.printf "new box: %f, %f, %f, %f\n" nminx nminy nmaxx nmaxy;*)
         {p with
           Pdfpage.mediabox = Pdf.Array [Pdf.Real nminx; Pdf.Real nminy; Pdf.Real nmaxx; Pdf.Real nmaxy];
           Pdfpage.rest = erase_boxes p.Pdfpage.rest}
     in
     let minx, miny, maxx, maxy = get_box pdf p in
-    (*Printf.printf "minx, miny, maxx, maxy = %f, %f, %f, %f\n" minx miny maxx maxy;*)
     let w, h = (maxx -. minx) /. float_of_int x, (maxy -. miny) /. float_of_int y in
     let ps = ref [] in
       make_pages x y columns btt rtl w h ps (move_page minx miny p w h);
       rev !ps
 
-(* Chop pages in the range into pieces *)
 let chop ~x ~y ~columns ~btt ~rtl pdf range =
   let pages = Pdfpage.pages_of_pagetree pdf in
   let pages_out =
@@ -56,5 +66,4 @@ let chop ~x ~y ~columns ~btt ~rtl pdf range =
            (ilist 1 (Pdfpage.endpage pdf))
            pages)
   in
-    (*iter (fun (a, b) -> Printf.printf "%i -> %i\n" a b) changes;*)
     Pdfpage.change_pages ~changes true pdf pages_out