OpenComputers Robot farmer

local robot = require("robot")
local comp = require("computer")

local size = 9

function harvest()
  -- fly to start
  robot.forward()
  for y=1, size do
    -- harvest one line
    robot.swingDown()
    robot.useDown()
    robot.placeDown()
    for x=1, (size-1) do
      robot.forward()
      robot.swingDown()
      robot.useDown()
      robot.placeDown()
    end
        -- turn
    if y%2 == 1 then
          robot.turnLeft()
          robot.forward()
          robot.turnLeft()
        else
          robot.turnRight()
          robot.forward()
          robot.turnRight()
        end
  end
  -- return
  for y=1, (size-1) do
    robot.forward()
  end
  robot.turnLeft()
  for y=1, (size) do
    robot.forward()
  end
  robot.turnRight()
  robot.forward()
  robot.turnAround()
end

function unload()
  robot.turnAround()
  for c = 2, 16 do
    robot.select(c)
    if robot.count() > 0 then
      robot.drop()
    else
      robot.select(1)
      break
    end
  end
  robot.turnAround()
end

while true do
 harvest()
  if robot.count(2) == 64 then
    unload()
  end

  -- one hour sleeping
  for i=1, 100 do
    os.sleep(36)
    print((1*i)..'%')
  end
  --
end