Oreberry farm chunk OC

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

function harvest()
robot.forward()
  for y=1, 15 do
    -- harvest one line
    robot.useDown()
    robot.useUp()
    robot.suck()
    robot.suck()
    for x=1, 15 do
      robot.forward()
      robot.useDown()
      robot.useUp()
      robot.suck()
      robot.suck()
    end
        -- povorot
        --esli y nechetnoe to
    if y%2 == 1 then
          robot.turnLeft()
          robot.forward()
          robot.turnLeft()
        else
          robot.turnRight()
          robot.forward()
          robot.turnRight()
        end
  end
  -- na posledneij linii
      robot.useDown()
      robot.useUp()
      robot.suck()
      robot.suck()
for x=1, 15 do
      robot.forward()
      robot.useDown()
      robot.useUp()
      robot.suck()
      robot.suck()
    end
  -- vozvrat
       robot.turnLeft()
           while robot.detect()==false do
           robot.forward()
           end
       robot.turnLeft()
       end
end

function unload()
  for c = 1, 32 do
    robot.select(c)
    robot.dropDown()
    end
  end
end

while true do
  harvest()
  unload()
  print('sleep')
  os.sleep(1800)
end