Vampire off revenants—are common in vampire folklore. Garlic is a common example, a branch of wild rose and hawthorn plant are said to harm vampires, and in Europe, sprinkling mustard seeds on the roof of a house was said to keep them away. Other apotropaics include sacred items, for example a crucifix, rosary, or holy water. Vampires are said to be unable to walk on consecrated ground, such as that of churches or temples, or cross running water. Although not traditionally regarded as an apotropaic, mirrors have been used to ward off vampires when placed, facing outwards, on a door (in
Barrier resilience of the same size as each other with bounded aspect ratios. For unit disks without assuming bounded ply, the problem of computing the resilience may be approximated to within a constant factor, using the fact that for this shape of barrier the optimal path can only cross each barrier a constant number of times, so the barrier thickness and barrier resilience are within a constant factor of each other. Similar methods can be generalized to non-uniform sensors of approximately equal size. Barrier resilience Barrier resilience is an algorithmic optimization problem in computational geometry motivated by the design of wireless sensor