Editing Moiré pattern (section)

=== {{Anchor|Inogon light|Inogon leading mark}} Marine navigation ===
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.<ref>{{cite web|title=US Patent 4,629,325|url=https://patents.google.com/patent/US4629325|website=Google Patents|access-date=5 March 2018}}</ref><ref>{{cite web|author=Alexander Trabas |url=http://www.listoflights.org/leuchtfeuer/detail?id=487 |title=Prohibited anchorage |publisher=Light of Lights |access-date=9 December 2016}}</ref><ref>{{cite book |title=Hydrographic Dictionary |date=2003 |publisher=[[International Hydrographic Organization]] |location=Monaco |page=113 |edition=5 |chapter=inogen light {{sic}}}}</ref> An example can be found in the UK on the eastern shore of [[Southampton Water]], opposite [[Fawley Refinery|Fawley oil refinery]] ({{coord|50|51|21.63|N|1|19|44.77|W|type:landmark_region:GB|display=inline}}).<ref>{{Citation|first=Tom|last=Scott|author-link=Tom Scott (presenter)|title=The Moiré Effect Lights That Guide Ships Home|date=5 March 2018|url=https://www.youtube.com/watch?v=d99_h30swtM|access-date=5 March 2018}}</ref> 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.
Inogon lights are deployed at airports to help pilots on the ground keep to the centreline while docking on stand.<ref>{{cite book |last1=Kazda |first1=Antonín |last2=Caves |first2=Robert |title=Airport design and operation |date=2015 |publisher=Emerald |location=Bingley, England |isbn=9781784418700 |pages=204–205 |edition=3}}</ref>