View difference between Paste ID: E2DT1kzx and xw45DNzy

 local length = 61
 local width = 61
 
 local function refuel()
 	if turtle.getFuelLevel() < 50 then
 		local prev = turtle.getSelectedSlot()
 		turtle.select(1)
 		if not turtle.refuel(4) then
 			print('Need more fuel')
 			while not turtle.refuel(4) do
 				sleep(3)
 			end
 		end
 		turtle.select(prev)
 	end
 end
 
-local function tryForwards()
+local function tryBackwards()
 	refuel()
-	while not turtle.forward() do
+	turtle.back()
-		if turtle.detect() then
+
-			turtle.dig()
+
-			sleep(.5)
+
-			while turtle.detect() do
+
-				turtle.dig()
+
-				sleep(.5)
+
 		while empty do
-		elseif turtle.attack() then
+
-		else
+
-			sleep(1)
+
                     empty = false
                     turtle.select(n)
                     return
                 end
             end
 			sleep(3)
 		end
 	else
 		turtle.select(turtle.getSelectedSlot() + 1)
 	end
 end
 
 local function placeBlock()
 	for i = 0, 2, 1 do
 		if not turtle.place() or turtle.getItemCount() == 0 then
     		while turtle.getItemCount() == 0 do
         		advance()
 			end
 		end
 	end
 end
 
 local function turnAround(i)
 	if i%2 == 1 then
 		turtle.turnRight()
-	if not turtle.detectDown() then
+		tryBackwards()
-		if not turtle.placeDown() or turtle.getItemCount() == 0 or turtle.getItemDetail().name ~= "minecraft:stone_slab" then
+
-			while turtle.getItemCount() == 0 or turtle.getItemDetail().name ~= "minecraft:stone_slab" do
+
-				advance()
+
 		turtle.turnLeft()
 		tryBackwards()
 		placeBlock()
 		turtle.turnLeft()
 	end
-	turtle.placeDown()
+
 turtle.select(2)
 for i = 1, length, 1 do
-		tryForwards()
+
 		refuel()
 		tryBackwards()
 		placeBlock()
-		turtle.forward()
+
 	turnAround(i)
 end