Within Atmosphere
The cloud that really looks like a saucer
Lenticular clouds can look like smooth hovering craft because mountain waves hold their lens shape in place.
On this page
- Why mountain waves form lens clouds
- Why they seem stationary while air moves through them
- Best sighting clues: terrain, wind and sunset light
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Introduction
Few natural phenomena have contributed more to classic “flying saucer” reports than lenticular clouds. Their smooth, lens-shaped outlines, stacked layers and apparent ability to hover motionless can make them look remarkably artificial, especially when illuminated by low-angle sunlight. Meteorological agencies, observatories and atmospheric scientists routinely cite lenticular clouds as one of the most common weather-related explanations for saucer-shaped UFO sightings. The resemblance is not superficial: many lenticular clouds possess the exact disc-like profile popularised in twentieth-century UFO culture. [Geophysical Institute]gi.alaska.eduflying saucer cloudsGeophysical InstituteFlying Saucer Clouds9 Mar 1987 — The clouds most likely to produce flying saucer reports are lenticular clouds, whic…
Within the broader category of clouds and atmospheric distortions that generate UFO reports, lenticular clouds occupy a special place because they can genuinely appear structured, stationary and machine-like. Unlike many mistaken identifications that depend on darkness, haze or distance, lenticular clouds can fool observers in broad daylight. Understanding why they form and why they look so unusual explains why generations of witnesses have interpreted them as hovering craft rather than ordinary weather.
The Cloud That Really Looks Like a Saucer
Lenticular clouds are named after the Latin word for “lens”. Meteorologists classify many of them as Altocumulus Standing Lenticular (ACSL) clouds. Their defining characteristic is a smooth, curved profile that often resembles a flattened disc, an almond, a stack of plates or a classic flying saucer. National Weather Service [NOAA NESDIS]nesdis.noaa.govtypes of cloudsNOAA NESDISTypes of Clouds | NESDIS31 Aug 2025 — Lenticular clouds are shaped like lenses or almonds or…flying saucers! They may get th…
Unlike most clouds, lenticulars frequently lack the ragged edges and constantly changing forms that people associate with atmospheric phenomena. They can display sharply defined outlines, layered bands and symmetrical contours. In photographs, particularly when seen from below, they often appear more like manufactured objects than clouds. National Weather Service guidance specifically notes that lenticular clouds develop distinctive lens-shaped forms within mountain-wave systems and can remain fixed in position despite strong winds. [National Weather Service]weather.govNational Weather ServiceAltocumulus Standing Lenticular CloudsWhen sufficient moisture is present above mountain-top level, ACSL clouds d…
Their appearance has become so strongly associated with UFOs that weather forecasters regularly refer to them informally as “UFO clouds”. National Geographic, EarthSky and numerous meteorological organisations have highlighted the resemblance in public explanations of unusual cloud sightings. [National Geographic]nationalgeographic.com151109 ufo clouds cape town lenticular clouds weather scienceNational Geographic'UFO Clouds' Are Real. Here's How They Happen9 Nov 2015 — Meteorologists call them lenticular clouds, which form when… [EarthSky]earthsky.orgbest photos beautiful lenticular clouds around the worldEarthSkyLenticular clouds look like UFOs1 Jan 2024 — Lenticular clouds are lens-shaped or saucer-shaped clouds. They typically form where…
Why Mountain Waves Form Lens Clouds
The mechanism behind lenticular clouds is well understood and involves airflow interacting with terrain.
When stable, moist air encounters a mountain range or elevated terrain, the air is forced upward. Instead of simply descending on the far side, the atmosphere can begin oscillating in a series of standing waves extending downwind of the mountains. Atmospheric scientists often compare the process to water flowing over a submerged rock in a river, producing stationary wave patterns downstream. [ERAU Weather]wx.erau.eduERAU Weathermountain_wavesMountain waves are standing atmospheric waves caused by airflow over mountains, analogous to standing waves in… [Center for Science Education]scied.ucar.eduForm Due to Mountains | Center for Science EducationSome clouds form when air encounters a mountain range or other types of terrain. When…
At the crest of each wave, air rises and cools. If the temperature falls to the dew point, water vapour condenses into visible cloud droplets. At the trough of the wave, the air sinks, warms and the cloud evaporates. The result is a cloud that forms repeatedly at the same location within the wave pattern. National Weather Service EarthSky The cloud therefore marks the position of the atmospheric wave rather than a discrete parcel of air. This distinction is crucial. The cloud’s [earthsky.org]earthsky.orgbest photos beautiful lenticular clouds around the worldEarthSkyLenticular clouds look like UFOs1 Jan 2024 — Lenticular clouds are lens-shaped or saucer-shaped clouds. They typically form where… visible shape can remain in the same place even though the air composing it is continuously moving through the system. National Weather Service [Center for Science Education]scied.ucar.eduForm Due to Mountains | Center for Science EducationSome clouds form when air encounters a mountain range or other types of terrain. When…
Mountain ranges around the world create ideal conditions for these formations. Lenticular clouds are particularly common near ranges such as the Rockies, the Sierra Nevada, the Cascades, the Southern Alps of New Zealand and isolated volcanic peaks such as Mount Fuji and Mount Shasta. The Sun [National Geographic]nationalgeographic.com151109 ufo clouds cape town lenticular clouds weather scienceNational Geographic'UFO Clouds' Are Real. Here's How They Happen9 Nov 2015 — Meteorologists call them lenticular clouds, which form when… [EarthSky]earthsky.orgbest photos beautiful lenticular clouds around the worldEarthSkyLenticular clouds look like UFOs1 Jan 2024 — Lenticular clouds are lens-shaped or saucer-shaped clouds. They typically form where…
Why They Seem Stationary While Air Moves Through Them
One reason lenticular clouds generate UFO reports is that they violate everyday expectations about cloud behaviour.
Most clouds drift visibly with the wind. Observers naturally assume that any cloud should move across the sky. Lenticular clouds often appear not to move at all. In reality, the cloud is continuously forming and dissipating in the same location within the standing wave. Moist air enters one side of the formation, condenses, then evaporates as it exits the other side. The visible cloud remains nearly fixed even while the air itself is travelling rapidly. National Weather Service [Center for Science Education]scied.ucar.eduForm Due to Mountains | Center for Science EducationSome clouds form when air encounters a mountain range or other types of terrain. When…
The National Weather Service explains that ACSL clouds are continually developing and dissipating near wave crests, which is precisely why they appear stationary despite sometimes very strong winds passing through them. [National Weather Service]weather.govNational Weather ServiceAltocumulus Standing Lenticular CloudsWhen sufficient moisture is present above mountain-top level, ACSL clouds d…
To a witness unfamiliar with atmospheric wave systems, this can create a striking illusion. A large disc-shaped object appears to hover over a mountain or ridge for extended periods without changing position. Human observers often associate hovering with powered flight, leading to interpretations involving advanced aircraft or extraterrestrial vehicles rather than weather. [Geophysical Institute]gi.alaska.eduflying saucer cloudsGeophysical InstituteFlying Saucer Clouds9 Mar 1987 — The clouds most likely to produce flying saucer reports are lenticular clouds, whic…
The illusion becomes even stronger when a lenticular cloud maintains its position for hours while ordinary clouds drift around it. The contrast reinforces the impression that the object is behaving differently from the surrounding atmosphere.
Why Sunset Light Makes the Illusion Stronger
Lighting conditions frequently determine whether a lenticular cloud is recognised as a cloud or reported as something mysterious.
Near sunrise and sunset, low-angle sunlight illuminates the smooth surfaces of lenticular clouds in ways that emphasise their apparent solidity. Their curved forms can display bright upper surfaces and darker undersides, producing shading patterns similar to those seen on physical objects. [National Geographic]nationalgeographic.com151109 ufo clouds cape town lenticular clouds weather scienceNational Geographic'UFO Clouds' Are Real. Here's How They Happen9 Nov 2015 — Meteorologists call them lenticular clouds, which form when…
Under certain conditions, multiple stacked layers develop within the same wave system. These layers can resemble decks, tiers or structural components of a craft. When the setting Sun illuminates only portions of the cloud, the effect can appear even more artificial. Observers often describe these formations as metallic, glowing or structured despite their entirely natural origin. [EarthSky]earthsky.orgbest photos beautiful lenticular clouds around the worldEarthSkyLenticular clouds look like UFOs1 Jan 2024 — Lenticular clouds are lens-shaped or saucer-shaped clouds. They typically form where…
Photographs that later circulate on social media frequently amplify the effect. Telephoto lenses compress perspective, making the cloud appear denser and more sharply bounded than it seemed to the naked eye. This contributes to periodic waves of online speculation whenever particularly dramatic lenticular formations appear.
Historical and Modern UFO Associations
The connection between lenticular clouds and UFO reports extends back decades. [rebeccalexa.com]rebeccalexa.comwhat causes lenticular clouds?Oct 26, 2021 — If the air is stable and fast moving, this causes it to ripple, and if there's enough humidity for clouds to form within…
The Alaska Science Forum noted as early as 1987 that lenticular clouds were among the cloud types most likely to generate flying saucer reports. In Alaska, where mountain-wave conditions are common during winter, these formations have long attracted attention from observers unfamiliar with their origin. [Geophysical Institute]gi.alaska.eduflying saucer cloudsGeophysical InstituteFlying Saucer Clouds9 Mar 1987 — The clouds most likely to produce flying saucer reports are lenticular clouds, whic…
Modern examples continue to emerge regularly. In Scotland, unusual lenticular formations prompted widespread public discussion and media coverage, with meteorologists explaining that the clouds’ saucer-like appearance frequently leads to UFO interpretations. [Daily Record]dailyrecord.co.ukbaffled scots spot ufo shaped 26514073The orb-shaped clouds were visible across the…Read more…
A striking example occurred above Cape Town in 2015, where photographs of a dramatic lenticular cloud spread widely online because of its apparent resemblance to a hovering spacecraft. Meteorologists explained that the city’s mountainous terrain and prevailing winds create ideal conditions for mountain-wave clouds. [National Geographic]nationalgeographic.com151109 ufo clouds cape town lenticular clouds weather scienceNational Geographic'UFO Clouds' Are Real. Here's How They Happen9 Nov 2015 — Meteorologists call them lenticular clouds, which form when…
New Zealand’s famous “Taieri Pet” provides an especially instructive case. This recurring lenticular cloud appears repeatedly in nearly the same location because the surrounding terrain generates the same atmospheric wave pattern. Residents have observed it for well over a century, yet newcomers continue to find its appearance startling because it seems unnaturally fixed in the sky. [The Sun]thesun.co.ukThe phenomenon, captured by a NASA satellite in September and last seen by an Air New Zealand pilot in 2020, is an elongated altocumulus…
These recurring examples demonstrate that UFO interpretations often arise not because the phenomenon is unexplained but because its appearance conflicts with ordinary expectations about how clouds should behave.
Best Sighting Clues: Terrain, Wind and Cloud Structure
Several clues can help distinguish a lenticular cloud from an unidentified aerial object.
Mountainous terrain: Lenticular clouds are strongly associated with mountains, ridges and elevated terrain. A saucer-shaped object observed downwind of a mountain range is more likely to be a lenticular cloud than a structured craft. [National Weather Service]weather.govNational Weather ServiceAltocumulus Standing Lenticular CloudsWhen sufficient moisture is present above mountain-top level, ACSL clouds d… [Hong Kong Observatory]hko.gov.hk00468 mountain wave cloudsHong Kong ObservatoryMountain Wave Clouds19 Jul 2022 — Under stable atmospheric condition, the air after passing through the mountain top…
Strong, stable airflow: These clouds form when stable air flows across terrain and produces standing waves. Their presence often indicates substantial winds aloft, even if conditions at ground level seem calm. [National Weather Service]weather.govNational Weather ServiceAltocumulus Standing Lenticular CloudsWhen sufficient moisture is present above mountain-top level, ACSL clouds d…
Smooth edges: Lenticular clouds typically display unusually smooth boundaries and may appear layered like stacked pancakes. While this can look artificial, it is characteristic of wave-cloud formation. [EarthSky]earthsky.orgbest photos beautiful lenticular clouds around the worldEarthSkyLenticular clouds look like UFOs1 Jan 2024 — Lenticular clouds are lens-shaped or saucer-shaped clouds. They typically form where…
Long-lasting position: A lenticular cloud may remain almost fixed relative to a mountain for extended periods. Apparently motionless behaviour is therefore not evidence against a cloud explanation; it is one of the defining characteristics of the phenomenon. National Weather Service [Center for Science Education]scied.ucar.eduForm Due to Mountains | Center for Science EducationSome clouds form when air encounters a mountain range or other types of terrain. When…
Gradual shape evolution: Although seemingly stationary, lenticular clouds slowly grow, shrink and reform. Careful observation over time often reveals subtle atmospheric changes inconsistent with a solid object. [Yahoo]yahoo.comlenticular clouds sometimes mistaken ufos 150745839YahooLenticular clouds, sometimes mistaken for UFOs, are in a…25 Sept 2024 — Lenticular clouds are different from other clouds because…
Why Lenticular Clouds Remain One of the Strongest UFO Explanations
Many weather-related UFO explanations depend on poor visibility, darkness or optical distortion. Lenticular clouds are different. They can look extraordinary even under ideal viewing conditions.
Their disc-like geometry, smooth surfaces, layered appearance and apparent ability to hover combine several features that people instinctively associate with engineered objects. At the same time, atmospheric science provides a clear and extensively documented mechanism explaining exactly how such formations arise. Mountain-wave dynamics, condensation within standing waves and continuous cloud regeneration account for both their appearance and their behaviour. Hong Kong Observatory 3National Weather Service [ERAU Weather]wx.erau.eduERAU Weathermountain_wavesMountain waves are standing atmospheric waves caused by airflow over mountains, analogous to standing waves in…
For that reason, lenticular clouds remain one of the most persuasive examples of how a completely natural atmospheric phenomenon can produce sightings that genuinely resemble the popular image of a flying saucer. Rather than being a weak or dismissive explanation, they represent a case where the atmosphere itself creates something that looks remarkably close to the UFO stereotype. [Geophysical Institute]gi.alaska.eduflying saucer cloudsGeophysical InstituteFlying Saucer Clouds9 Mar 1987 — The clouds most likely to produce flying saucer reports are lenticular clouds, whic…
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Endnotes
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Source: facebook.com
Link: https://www.facebook.com/metoffice/photos/owing-to-their-distinctive-oval-shape-lenticular-clouds-have-often-been-mistaken/10152570754964209/Source snippet
staken as #UFO sightings. They form when the air is stable and...
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Source: gi.alaska.edu
Title: flying saucer clouds
Link: https://www.gi.alaska.edu/alaska-science-forum/flying-saucer-cloudsSource snippet
Geophysical InstituteFlying Saucer Clouds9 Mar 1987 — The clouds most likely to produce flying saucer reports are lenticular clouds, whic...
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Source: nesdis.noaa.gov
Title: types of clouds
Link: https://www.nesdis.noaa.gov/about/k-12-education/atmosphere/types-of-cloudsSource snippet
NOAA NESDISTypes of Clouds | NESDIS31 Aug 2025 — Lenticular clouds are shaped like lenses or almonds or...flying saucers! They may get th...
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Source: weather.gov
Link: https://www.weather.gov/abq/features_acslSource snippet
National Weather ServiceAltocumulus Standing Lenticular CloudsWhen sufficient moisture is present above mountain-top level, ACSL clouds d...
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Source: earthsky.org
Title: best photos beautiful lenticular clouds around the world
Link: https://earthsky.org/earth/best-photos-beautiful-lenticular-clouds-around-the-world/Source snippet
EarthSkyLenticular clouds look like UFOs1 Jan 2024 — Lenticular clouds are lens-shaped or saucer-shaped clouds. They typically form where...
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Source: wx.erau.edu
Link: https://wx.erau.edu/faculty/mullerb/Wx365/Mountain_waves/mountain_waves.htmlSource snippet
ERAU Weathermountain_wavesMountain waves are standing atmospheric waves caused by airflow over mountains, analogous to standing waves in...
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Source: yahoo.com
Title: lenticular clouds sometimes mistaken ufos 150745839
Link: https://www.yahoo.com/news/lenticular-clouds-sometimes-mistaken-ufos-150745839.htmlSource snippet
YahooLenticular clouds, sometimes mistaken for UFOs, are in a...25 Sept 2024 — Lenticular clouds are different from other clouds because...
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Source: facebook.com
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e, so it creates waves in the wind- flow, the rising air...Read more...
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Source: facebook.com
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That wasn't a UFO. It was a rare lenticular cloudMet Office Lenticular clouds: UFO-like clouds spotted in Scottish... These are often mi...
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Source: facebook.com
Title: ️ whats up with that ufo cloudspotted a wild looking cloud today thats a lenticu
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Source: psl.noaa.gov
Link: https://psl.noaa.gov/outreach/education/pdf/AC00572.pdfSource snippet
mountain waves are present, it is quite common for a rotor zone to develop near or below ridge level on the downwind side of the mountain...
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Title: 151109 ufo clouds cape town lenticular clouds weather science
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National Geographic'UFO Clouds' Are Real. Here's How They Happen9 Nov 2015 — Meteorologists call them lenticular clouds, which form when...
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Form Due to Mountains | Center for Science EducationSome clouds form when air encounters a mountain range or other types of terrain. When...
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Source: hko.gov.hk
Title: 00468 mountain wave clouds
Link: https://www.hko.gov.hk/en/education/weather/clouds/00468-mountain-wave-clouds.htmlSource snippet
Hong Kong ObservatoryMountain Wave Clouds19 Jul 2022 — Under stable atmospheric condition, the air after passing through the mountain top...
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Title: Center for Science Education Lenticular Clouds
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Clouds - UCAR Center for Science EducationLenticular, or lee wave, clouds form downwind of an obstacle in the path of a strong air curren...
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Source: thesun.co.uk
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The phenomenon, captured by a NASA satellite in September and last seen by an Air New Zealand pilot in 2020, is an elongated altocumulus...
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Source: dailyrecord.co.uk
Title: baffled scots spot ufo shaped 26514073
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The orb-shaped clouds were visible across the...Read more...
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Title: Lenticular cloud
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Lenticular cloudLenticular clouds are stationary clouds that form mostly in the troposphere, typically in parallel alignment to the wi...
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Title: Mountain Waves | SKYbrary Aviation Safety Cloud Formation
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Lenticular Clouds (lens shaped clouds) can form in the crest of the mountain waves if the air is moist. Roll Clouds can also occur in the...
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Source: rebeccalexa.com
Title: what causes lenticular clouds
Link: https://rebeccalexa.com/what-causes-lenticular-clouds/Source snippet
?Oct 26, 2021 — If the air is stable and fast moving, this causes it to ripple, and if there's enough humidity for clouds to form within...
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Additional References
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Link: https://www.premierflightct.com/newsletters/TrainingArticles/StandingLenticularClouds.htmlSource snippet
Standing Lenticular CloudsStanding lenticular clouds form in the crests of the mountain wave where the rising updraft of the wave has coo...
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Source: x.com
Link: https://x.com/Daily_Record/status/1768307457271509191Source snippet
X (formerly Twitter)Met Office explains 'UFO shaped clouds' spotted across...The Daily Record (@Daily_Record). Met Office explains 'UFO...
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Source: gibbs.science
Link: https://gibbs.science/teaching/mesoscale/handouts/lecture_notes_03.pdf -
Source: mountwashington.org
Link: https://mountwashington.org/a-closer-look-at-lenticular-clouds/ -
Source: journals.ametsoc.org
Title: Furthermore, we suggest that the lenticular clouds may not be formed in all wave
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American Meteorological Society JournalsA Modeling Study of a Trapped Lee-Wave Event over the...by M Udina · 2017 · Cited by 24 — Althou...
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Link: https://www.youtube.com/watch?v=KgO7Kyq3q-USource snippet
Lenticular CloudsLenticular clouds are also known as lenticularis because they are shaped like a lens. They are common over mountains whe...
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Source: reddit.com
Link: https://www.reddit.com/r/flying/comments/i9n4a0/what_is_happening_inside_the_lenticular_clouds/Source snippet
The stable air is forced up and over the mountains, causing it to condense into a...Read more...
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Source: space.com
Title: flying saucer cloud gemini observatory photo
Link: https://www.space.com/flying-saucer-cloud-gemini-observatory-photoSource snippet
Flying saucer-shaped cloud floats above Hawaiian...14 Aug 2022 — Lenticular clouds, sometimes called "UFO clouds," form when fast winds...
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Source: journals.ametsoc.org
Title: 1520 0469 1997 054 1308 osaaon 2.0.co 2.xml
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ametsoc.orgObservations, Simulations, and Analysis of Nonstationary...by FM Ralph · 1997 · Cited by 120 — At a lower altitude (near 3.7...
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'Lenticular clouds' over Cape Town real, but photo 5 years...21 Aug 2020 — And the Met Office says that [pilots]({{ 'pilots/' | relative_url }}) tend to avoid lenticular...
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