diff --git a/mystical-upgrader.lua b/mystical-upgrader.lua
index b609c47..754698e 100644
--- a/mystical-upgrader.lua
+++ b/mystical-upgrader.lua
@@ -1,4 +1,9 @@
+local turtleUtils = require('libs/turtle-utils')
+
+local NB_ROWS = 1
+local DIRECTION = 'right' -- 'left' | 'right'
 local FILL_BLOCK = 'minecraft:cobblestone'
+
 local LEVEL_PER_TIER = 12
 
 local formatBlockName = function(tierName)
@@ -54,6 +59,33 @@ local refuel = function()
   end
 end
 
+local goToTheLeft = function()
+  turtle.turnLeft()
+  local ok, reason = turtle.forward()
+
+  if not ok then
+    error('cannot forward because ' .. tostring(reason), 0)
+  end
+
+  turtle.turnRight()
+end
+
+local goToTheRight = function()
+  turtle.turnRight()
+  local ok, reason = turtle.forward()
+
+  if not ok then
+    error('cannot forward because ' .. tostring(reason), 0)
+  end
+
+  turtle.turnLeft()
+end
+
+local MOVES = {
+  left = goToTheLeft,
+  right = goToTheRight,
+}
+
 local getTierFromLevel = function(level)
   return math.floor((level - 1) / LEVEL_PER_TIER) + 1
 end
@@ -73,10 +105,10 @@ local inspectBlockName = function()
   return block and block.name
 end
 
-local selectBlock = function(blockName)
+local selectBlock = function(itemName)
   for i=1, 16, 1 do
     local details = turtle.getItemDetail(i)
-    if details and details.name == blockName then
+    if details and details.name == itemName then
       turtle.select(i)
       return true
     end
@@ -109,26 +141,31 @@ local placeDownFillBlock = function()
 end
 
 -- Main state and stateful methods
-local state = {
-  y = 1,
-  initialLevel = 0,
-  newLevel = 0,
-  errorLevel = nil
-}
+local function getInitialState()
+  return {
+    firstPickedItem = nil,
+    y = 1,
+    initialLevel = 0,
+    newLevel = 0,
+    errorLevel = nil
+  }
+end
 
-local digAndGoDown = function()
+-- local state = getInitialState()
+
+local digAndGoDown = function(state)
   turtle.digDown()
   turtle.down()
   state.y = state.y + 1
 end
 
-local goUp = function()
+local goUp = function(state)
   turtle.up()
   state.y = state.y - 1
 end
 
 -- 1. down procedure
-local downProcedure = function()
+local downProcedure = function(state)
   while state.y < 60 do
     local replaced = replaceBlockAt(state.y)
 
@@ -146,20 +183,20 @@ local downProcedure = function()
       break
     end
 
-    digAndGoDown()
+    digAndGoDown(state)
   end
 end
 
 -- 2. up procedure
-local upProcedure = function()
+local upProcedure = function(state)
   while state.y ~= 1 do
-    goUp()
+    goUp(state)
     placeDownFillBlock()
   end
 end
 
 -- 3. print report
-local printReport = function()
+local printReport = function(state)
   local initialLevel = state.initialLevel
   if initialLevel == nil then
     initialLevel = 'nil'
@@ -174,15 +211,32 @@ local printReport = function()
   end
 end
 
+local upgradeProcedure = function()
+  turtleUtils.compactInventory()
+
+  local state = getInitialState()
+
+  downProcedure(state)
+  upProcedure(state)
+  printReport(state)
+
+  return state
+end
+
 -- Main function
 local main = function()
   assertEnoughFillBlocks()
   refuel()
   assertEnoughFuel()
 
-  downProcedure()
-  upProcedure()
-  printReport()
+  for i=1, NB_ROWS, 16 do
+    upgradeProcedure()
+
+    if i ~= NB_ROWS then
+      MOVES[DIRECTION]()
+    end
+  end
+
 end
 
 main()