From an outside perspective forming looks very easy, but it actually poses great difficulties. "For instance, each piece's proportions, angles, arcs, thickness, and even weight-all must be done to a high degree of accuracy," explains Tsai as he holds up a cup.
外在型制看似易仿，其實困難重重：「舉凡各部位的比例、角度、弧線、坯體厚薄，甚至重量，都必須分毫不差。」