The moiré effect is used in shoreside beacons called "Inogon leading marks" or "Inogon lights", manufactured by Inogon Licens AB, Sweden, to designate the safest path of travel for ships heading to locks, marinas, ports, etc., or to indicate underwater hazards (such as pipelines or cables). The moiré effect creates arrows that point towards an imaginary line marking the hazard or line of safe passage; as navigators pass over the line, the arrows on the beacon appear to become vertical bands before changing back to arrows pointing in the reverse direction.[9][10][11] An example can be found in the UK on the East shore of Southampton water, opposite Fawley oil refinery (50°51′21.63″N 1°19′44.77″W﻿ / ﻿50.8560083°N 1.3291028°W﻿ / 50.8560083; -1.3291028).[12] Similar moiré effect beacons can be used to guide mariners to the centre point of an oncoming bridge; when the vessel is aligned with the centreline, vertical lines are visible.