Low 3x3 tunnel digger

-- davial. Low 3x3 tunnel digger alpha 0.02

local r = require ("robot")
function Dig()
    r.swing()
    r.forward()
    r.swingUp()
    r.swingDown()
end
function RightHand()
    Dig()
    r.turnRight()
    Dig()
    r.forward()
    Dig()
    r.turnLeft()
end
function LeftHand()
    Dig()
    r.turnLeft()
    Dig()
    r.forward()
    Dig()
    r.turnRight()
end

-- Programm --

-- .. Length track ..
print (" Input length tunnel ")
len = io.read()

-- .. His say : "POYEHALI" ..
r.up()

for i = 1, len do
  if i%2~=0 then RightHand()
            else LeftHand()
  end
end

r.down()