A "node" may be the "child" of another node; in such a case, it becomes logical that multiple steps must be taken to carry out an attack. For example, consider classroom computers which are secured to the desks. To steal one, the securing cable must be cut or the lock unlocked. The lock may be unlocked by picking or by obtaining the key. The key may be obtained by threatening a key holder, bribing a keyholder, or taking it from where it is stored (e.g. under a mousemat). Thus a four level attack tree can be drawn, of which one path is ("Bribe Keyholder", "Obtain Key", "Unlock Lock", "Steal Computer").