《墨子·52章 备城门》
楼五十步一座，城堞下挖掘 爵穴 。每三尺设立一个桔槔，大二围，长四尺半，必须有挈。
楼五十步一，堞下为爵穴，三尺而一为薪皋，二围，长四尺半，必有洁。
Build towers fifty paces apart, and dig juxue beneath the battlements. Set up a jieji every three feet, with a circumference of two chi and a length of four and a half feet. It must have a hook.