Travel on the border
It is an idiom that refers to traveling around the world. From Wu Chengen's journey to the West.
Interpretation ascends the heaven and travels everywhere. Wu Chengen's journey to the West in Ming Dynasty is the first time: "the monkey king kowtowed and said:" I have traveled across the sea and traveled to the border. I only visited here for more than ten years. "
Travel on the border
compasses , set square , spirit level and plumb line - guī jǔ zhǔn shéng