fence

local X = 1
local Y = 1
for side = 1, 4 do
  for i = 1, 128 do
    turtle.digDown()
    turtle.placeDown()
    Y = turtle.getItemCount(X)
    if Y == 0 then
      X = X+1
      turtle.select(X)
      end
    turtle.dig()
    turtle.forward()
    end
  turtle.turnLeft()
  end