And in order to draw these shapes, the medieval craftsmen who did this would have done them by using these construction lines.

要画出这些图形，中世纪的匠人会借助这些辅助线。

I've got several thousand hours of carrying sling loads, fire buckets, concrete buckets, doing power line construction, actual power poles.

我已经有数千小时的搬运吊索负载的经验了，消防桶、混凝土桶、电力线路施工、实际的电线杆。