A metal device with four projecting spikes so arranged that when three of the spikes are on the ground, the fourth points upward, used as a hazard to pneumatic tires or to the hooves of horses.

• 铁蒺藜一种金属装置，有四只突出的脚钉，三只立于地上，第四只指向上方，用作气动轮胎的闸或马蹄