Explore MRSY's 20531 photos on Flickr!
Why is the cover of a manhole nearly always round? Why isn't it oval or square? Manhole covers are nearly always circular, but they may feature distinctive geometric designs, like the ring-and-spoke pattern shown here.. One answer is that a circular lid, unlike a square or an oval cover, won't fall through the opening. There's no way to position a round lid so that it can slip through a slightly smaller hole of the same shape. That's because a circle has a constant diameter. It has the same width all the way around. In contrast, an oval or an ellipse is longer than it is wide. You can always find a way to slip an oval lid through a hole of the same shape. That's also true of a square or a hexagonal cover. Plus signs add an arithmetical touch to this manhole cover in Pittsburgh. A 12-sided (dodecagonal) manhole cover shouldn't work, but if the hole is sufficiently smaller than the lid, the cover's shape may be close enough to a circle to work effectively. This 12-sided manhole cover near the U.S. Capitol features a triangular grid and a curious pattern of holes. Amazingly, the circle isn't the only shape that would work safely as a manhole cover. In fact, any shape of constant width would do, and there are infinitely many such shapes. The simplest example is the Reuleaux triangle, named after distinguished mechanical engineer Franz Reuleaux (1829–1905), who was a teacher in Berlin more than 100 years ago. A Reuleaux triangle (solid lines), based on an equilateral triangle (dashed lines) and set inside a square, is a geometric shape that has a constant width. One way to draw a Reuleaux triangle is to start with an equilateral triangle, which has three sides of equal length. Draw three arcs of circles, with each arc having as its center one of the triangle's corners and as its endpoints the other two corners. The resulting “curved triangle," as Reuleaux termed it, has a constant width equal to the length of the interior triangle's side. I haven't yet seen a manhole cover in the shape of a Reuleaux triangle, but I have heard that they exist. One can construct a curve of constant width not only from an equilateral triangle but also from any polygon with an odd number of sides. Thus, you can readily obtain a curved pentagon, heptagon, and so on. A Reuleaux pentagon and a Reuleaux heptagon (outer boundaries) are both curves of constant width. Some coins have a rounded heptagonal shape that allows their use in slot machines designed for ordinary coins. The Reuleaux curves described so far have corners—points where two sides meet at an angle. However, curves of constant width having rounded corners can be readily constructed from the angular forms. Moreover, a curve of constant width need not be symmetrical or even consist of circular arcs. Therefore, an unlimited number of curves of constant width are possible, and the Reuleaux triangle happens to be the family member of least area. Hexagons adorn a circular manhole cover in New Orleans. In principle, manhole cover designers have an infinite array of shapes at their disposal, but circular covers remain the norm. Photos by I. Peterson
Explore ccotton's 3467 photos on Flickr!
We have compiled a list of 25 unique manhole covers from all areas of the country.
HUNTSVILLE, Ala. – A WHNT News 19 viewer has an interesting question. How do you correct a misspelled manhole cover? Joel Elliott brought the error to our attention on Twitter. He’s absolutely right.. the city’s name is misspelled ‘Huntsivlle.’ There’s more than one of them. We stepped outside WHNT News 19, on Holmes Avenue, to […]
Photograph by S MORITA (MRSY on Flickr) In 95% of Japan’s 1,780 municipalities you will find artistic manhole covers unique to each city and town. It has become apart of the cou…
There are a lot of beautiful designed and colored manhole covers in Japan.
Photograph by S MORITA (MRSY on Flickr) In 95% of Japan’s 1,780 municipalities you will find artistic manhole covers unique to each city and town. It has become apart of the cou…
A photographic collection of some of NYC's most unique and artistic manhole covers with the oldest in the city on Jersey Street and a series by Public Art Fund
This manhole cover in Naumburg (Saale) displays the Naumburg Cathredal, a UNESCO World Heritage Site in the German state of Saxony-Anhalt.
I have taken a lot of beautiful Japanese manhole cover's photographs. I learnt there were a lot of beautiful manhole covers also in many countries.
Explore MRSY's 20537 photos on Flickr!
A blog about art and science and all the wonderful bits in-between!
Explore MRSY's 20538 photos on Flickr!
Link to introductory page Scandinavia has some of the most decorative manhole covers in Europe, with artistic and historical motifs, often representing major sites in the town. Especially worthy of note are the series of designs produced for Odense, probably relecting the fairy tales of Hans Christian Andersen. Aabenraa Frederikshavn Frederickshavn Hjorring Hjorring Odense Odense, horse Odense, tree sprite Odense, birds Randers Randers Silkeborg Silkeborg Link to introductory page
A manhole cover is generally deemed successful if its round shape keeps pedestrians from plummeting into the earth, and communicates the subterranean systems below through its design.
Link to introductory page Scandinavia has some of the most decorative manhole covers in Europe, with artistic and historical motifs, often representing major sites in the town. Especially worthy of note are the series of designs produced for Odense, probably relecting the fairy tales of Hans Christian Andersen. Aabenraa Frederikshavn Frederickshavn Hjorring Hjorring Odense Odense, horse Odense, tree sprite Odense, birds Randers Randers Silkeborg Silkeborg Link to introductory page
Sometimes, you have to look down at your feet to discover small treasures hidden in plain sight. These are some of the beautiful Japanese manhole covers with amazing designs and colors.
A manhole cover is generally deemed successful if its round shape keeps pedestrians from plummeting into the earth, and communicates the subterranean systems below through its design.
One of my favorite book discoveries this summer is Drainspotting by Remo Camerota. The book celebrates an array of fascinating manhole cover designs from Japan. According to Camerota, nearly 95% of the 1,780 municipalities in Japan have their very own customized manhole covers. The country has elevated this humble, practical object to its […]
Sometimes, you have to look down at your feet to discover small treasures hidden in plain sight. These are some of the beautiful Japanese manhole covers with amazing designs and colors.
Manhole covers don’t have to be ugly sewer lids. In Japan, they can be astoundingly intricate, colorful, museum-worthy feats of urban design. Photographer
Download this free photo of Manhole Cover Channel Lid Bremer from Pixabay's vast library of royalty-free stock images, videos and music.
