setupQuarry

local selection = 1
turtle.select(1)

local function placeFence()
  turtle.digDown()
  turtle.placeDown()
  if turtle.getItemCount(selection) == 0 then
  selection = selection + 1
  turtle.select(selection)
  end
end

placeFence()
for i = 1, 4 do
  for i = 1, 63 do
  turtle.dig()
  turtle.forward()
  placeFence()
  end
  turtle.turnLeft()
end