diff --git a/README.md b/README.md
index 6c238b9..137d4fa 100644
--- a/README.md
+++ b/README.md
@@ -33,5 +33,12 @@ https://www.instagram.com/p/CS4JRtonRD7/
 	4. Open **code/toga/lib/togaarc.lua** file and repeat the step 2 and 3.
 	5. Reload the script on norns. Now **toga** will automatically connect to the TouchOSC controller when the script is loaded.
 
+## Orientation
+
+The orientation button says which round the grid should be oriented.
+Any change here only updates after clicking the connection button,
+so if you set or change the orientation on the grid, touch the connection
+button to register that.
+
 ## Forum
 https://llllllll.co/t/toga-touchosc-grid-and-arc-controller-for-monome-norns/47902
diff --git a/design.md b/design.md
new file mode 100644
index 0000000..4641e4d
--- /dev/null
+++ b/design.md
@@ -0,0 +1,29 @@
+# Design notes
+
+## Notes for `toga.tosc`
+
+The orientation of the grid is the orientation of the connect button.
+The script attached to the orientation button will change the orientation
+of the connect button, as well as changing the orientation lights.
+
+The OSC message `/toga_connection` has a send variant and a receive variant.
+When sent from the norns and received by TouchOSC the argument is the
+connect button's `x` value.
+When sent from TouchOSC and received by the norns the argument is the
+connect button's orientation.
+
+## Notes for `lib/togagrid.lua`
+
+`old_buffer` is what's been sent to the grid; `new_buffer` is the old buffer
+with any changes. This allows only changes to be sent on a refresh.
+
+`dest` is a list of tables, mapping IP address to port number, one for each
+connected grid.
+
+`orientation` is what the grid says its orientation is. 0 = north, 1 = east,
+2 = south, 3 = west. This is the orientation enumeration in TouchOSC.
+Regardless of how many grids are connected, there is only one orientation
+for all of them. Beware that the semantics is different from that used by
+`grid:rotation(val)` which is used to tell a (real)
+grid what orientation it should assume. There, the argument is
+0 = 0 degrees (east), 1 = 90 degrees (north), etc.
diff --git a/lib/togagrid.lua b/lib/togagrid.lua
index d18f3f7..470ffb9 100644
--- a/lib/togagrid.lua
+++ b/lib/togagrid.lua
@@ -12,7 +12,8 @@ local togagrid = {
   old_grid = nil,
   old_osc_in = nil,
   old_cleanup = nil,
-  key = nil -- key event callback
+  key = nil, -- key event callback
+  orientation = 0, -- As TouchOSC, clockwise from 0 = north
 }
 
 function togagrid:connect()
@@ -83,13 +84,13 @@ function togagrid.osc_in(path, args, from)
         table.insert(togagrid.dest, from)
         togagrid:refresh(true, from)
       end
+      local orientation_changed = togagrid:set_orientation(args[1])
       -- echo back anyway to update connection button value
       togagrid:send_connected(from, true)
       -- do not consume the event so togaarc can also add the new touchosc client.
     elseif string.starts(path, "/togagrid/") then
       i = tonumber(string.sub(path,11))
-      x = ((i-1) % 16) + 1
-      y = (i-1) // 16 + 1
+      x, y = togagrid:i_to_xy(i)
       z = args[1] // 1
       --print("togagrid_osc_in togagrid", i, x, y, z)
       if togagrid.key then
@@ -109,6 +110,55 @@ function togagrid.osc_in(path, args, from)
   end
 end
 
+function togagrid:set_orientation(orientation)
+  local changed = false
+  if orientation then
+    if self.orientation ~= orientation then
+      self.orientation = orientation
+      changed = true
+    end
+  end
+  if changed then
+    if orientation % 2 == 0 then
+      -- North or south
+      self.cols = 16
+      self.rows = 8
+    else
+      -- East or west
+      self.cols = 8
+      self.rows = 16
+    end
+    self.old_buffer = create_buffer(self.cols, self.rows)
+    self.new_buffer = create_buffer(self.cols, self.rows)
+    self:refresh(true)
+  end
+  return changed
+end
+
+function togagrid:i_to_xy(i)
+  local x, y
+  if togagrid.orientation == 0 then
+    -- North
+    x = ((i-1) % 16) + 1
+    y = (i-1) // 16 + 1
+  elseif togagrid.orientation == 1 then
+    -- East
+    x = (i-1) // 16 + 1
+    y = 16 - ((i-1) % 16)
+  elseif togagrid.orientation == 2 then
+    -- South
+    i = 129 - i
+    x = ((i-1) % 16) + 1
+    y = (i-1) // 16 + 1
+  else
+    -- West
+    i = 129 - i
+    x = (i-1) // 16 + 1
+    y = 16 - ((i-1) % 16)
+  end
+  return x, y
+end
+
 function togagrid:hook_osc_in()
   if self.old_osc_in ~= nil then return end
   --print("togagrid: hook old osc_in")
@@ -190,7 +240,7 @@ end
 
 function togagrid:update_led(c, r, target_dest)
   local z = self.new_buffer[c][r]
-  local i = c + (r-1) * self.cols
+  local i = self:cr_to_i(c, r)
   local addr = string.format("/togagrid/%d", i)
   --print("togagrid osc.send", addr, z)
   for d, dest in pairs(self.dest) do
@@ -202,6 +252,26 @@ function togagrid:update_led(c, r, target_dest)
   end
 end
 
+function togagrid:cr_to_i(c, r)
+  local i
+  if togagrid.orientation == 0 then
+    -- North
+    i = c + (r-1) * self.cols
+  elseif togagrid.orientation == 1 then
+    -- East
+    i = c*16 - (r-1)
+  elseif togagrid.orientation == 2 then
+    -- Sound
+    i = c + (r-1) * self.cols
+    i = 129 - i
+  else
+    -- West
+    i = c*16 - (r-1)
+    i = 129 - i
+  end
+  return i
+end
+
 function togagrid:send_connected(target_dest, connected)
   for d, dest in pairs(self.dest) do
     if target_dest and (target_dest[1] ~= dest[1] or target_dest[2] ~= dest[2]) then
@@ -212,4 +282,4 @@ function togagrid:send_connected(target_dest, connected)
   end
 end
 
-return togagrid
\ No newline at end of file
+return togagrid
diff --git a/toga.tosc b/toga.tosc
index ee96bd5..28a5ed7 100644
Binary files a/toga.tosc and b/toga.tosc differ