《宋史·列传·卷一百二十五》
三人为一组，以绳索连贯，每前进一步，即用拒马木堵塞退路，人进一步，拒马木也随之跟进一步，退无可退。
三人为伍，贯以韦索，每进一步，即用拒马拥之，人进一步，拒马亦进，退不可却。
The three men formed a group, joining themselves together with ropes. Every time they took a step forward, they used obstacles to block their retreat. Every time they took a step forward, they moved the obstacle forward with them, so they had no choice but to advance.