function isInFrontOf(name)
  local success,data = turtle.inspect();
  return success and data.name==name;
end

function isFrontEmpty()
  local success,data = turtle.inspect();
  return not success
end


function digObsidian()
  if isInFrontOf("minecraft:obsidian") then
    turtle.dig()
  end
end

function main(args)
  local n = 999
  if #args == 1 then
    n = tonumber(args[1])
  end
  for i=1,n do
    digObsidian()
    turtle.turnLeft()
    digObsidian()
    turtle.turnRight()
    turtle.turnRight()
    digObsidian()
    turtle.turnLeft()
    if not isFrontEmpty() then
      print("cant move")
      return
    end
    turtle.forward()
  end
end

main({...})