 A cord attached to the weight was wrapped around a drum attached to two steel wheels; when the weight fell, the wheels struck sparks against flint, igniting a set of fuses to multiple mines.A similar mechanism was used in the first wheellock musket in Europe as sketched by Leonardo da Vinci around 1500 AD.Another victim-operated device was the "underground sky-soaring thunder", which lured bounty hunters with halberds, pikes, and lances planted in the ground.