startup

local input = redstone.getInput("back")

print(input)
while true do
    input = redstone.getInput("back")
    if input == true then
      print(input)
      turtle.select(2)
      turtle.digUp()
      turtle.select(4)
      turtle.transferTo(2)
      turtle.select(1)
      turtle.placeUp()
      turtle.select(3)
      for i = 1,3 do
        turtle.placeUp()
      end
      sleep(1)
      redstone.setOutput("top", true)
    else
      print(input)
      redstone.setOutput("top", false)
      turtle.select(1)
      turtle.digUp()
      turtle.select(4)
      turtle.transferTo(1)
      turtle.select(2)
      turtle.place()
    end
    os.pullEvent("redstone")
end