CC: tofu4

-- tofu4
--  surround four directions with walls

turtle.up()  -- move up

-- make 4 sides of a square
for hen=1,4 do
  -- put 4 blocks in the ground
  for i=1,4 do
    turtle.forward()  -- move to next position
    turtle.placeDown()  -- put a block
  end

  turtle.turnRight()  -- turn 90 degrees to the right
end

turtle.up() -- move up

-- make 4 sides of a square
for hen=1,4 do
  -- put 4 blocks in the ground
  for i=1,4 do
    turtle.forward()  -- move to next position
    turtle.placeDown()  -- put a block
  end

  turtle.turnRight()  -- turn 90 degrees to the right
end

turtle.up() -- move up

-- make 4 sides of a square
for hen=1,4 do
  -- put 4 blocks in the ground
  for i=1,4 do
    turtle.forward()  -- move to next position
    turtle.placeDown()  -- put a block
  end

  turtle.turnRight()  -- turn 90 degrees to the right
end

turtle.up() -- move up