This blog will be offline for a few days.
For World Solar Challenge fans, the most recently updated teams list is here. It has been updated with preliminary scrutineering results.
This blog will be offline for a few days.
For World Solar Challenge fans, the most recently updated teams list is here. It has been updated with preliminary scrutineering results.
I will be following the Challenger class in the 2019 Bridgestone World Solar Challenge this October using a large wall map (based on this post) and some paper pointers. Use the image below to construct your own pointers, writing in the name of your favourite team if it’s missing (see here for a list of all teams). I’m still working on how best to visualise Cruiser class progress.
Previously, Belenos came 3rd at Albi Eco 18.
In this event, they were racing their car Sunracer.
In this event, they were racing their car Eleadora 1.
Here is a further update on the 44 teams (27 Challengers, 14 Cruisers, and 3 Adventure cars) from 21 countries entered in the 2019 Bridgestone World Solar Challenge in Australia this October. Below is my best understanding of the current team status, based on social media reports and the official list of teams. Teams are sorted in team number order. As always, you can click the social media links, and click images to zoom. I have also put together a Twitter list for the event.
This year, signage regulations were interpreted unusually strictly, so that several top teams had to perform major surgery on their vehicle bodies. There have also been a surprising number of pre-race accidents.
Asymmetric GaAs challenger (new car: Nuna X) – these are the champions formerly known as Nuon. See their 2017 aftermovie. The new car weighs just 135 kg (298 lbs) and has a unique asymmetrical rear (designed to take advantage of October winds coming primarily from the east). The car has clocked up many test kilometres. They revealed their car on 16 July (video). Part of their team was assigned to do a detailed Adelaide-to-Darwin reverse route survey. As always, their main pre-race base was Nightcliff Primary School in Darwin. Their secret weapon this year is a sharkskin surface. A crash during testing caused some minor car damage.
Monohull challenger (new car: Intikallpa V) – they have been working hard getting their car finished. They revealed their car on 13 September (pic). Painted on the side of the car is an Andean condor (Vultur gryphus).
Two-seat cruiser (SunSPEC 6) – their 2019 car is a modified version of their 2017 car SunSPEC 5. They revealed their car on 30 July (pic). Based on photographs and the 2017 rating scheme, I would expect their car practicality to score around 60%. They appear to be out of the race, with a serious problem of some kind.
Monohull single junction GaAs challenger (new team with car: Green Lightning) – their car is a bullet car resembling Michigan’s 2017 Novum. It looks so good that at this stage I’m calling them “best new team.” Their car has four-wheel steering at low speed and two-wheel steering at high speed. There are Dutch media reports about their plans, and they are vlogging weekly (in Dutch, but they have started adding English subtitles). They revealed their car on 12 June (video). The Netherlands 11th Airmobile Brigade provided some final training on dealing with unusual challenges. They ran the fastest lap at Hidden Valley (1:51:99 = 92.3 kph).
Asymmetric challenger (Lumen II Mk II) – they have been doing a lot of testing. They also planned new solar cells and a re-wrap for the car.
Asymmetric GaAs challenger (new car: BluePoint) – they are now sponsored by Agoria. They held a mock race with the old car. Their new car looks very similar. They revealed their car on 3 July (video). Their main pre-race base is Casuarina Senior College in Darwin.
Previously, Agoria came 6th at WSC 13; came 5th at WSC 15; came 3rd at WSC 17; came 3rd at Abu Dhabi 15; came 2nd at iESC 16; and came 6th at iESC 18. Their team number (8) is a long-standing tradition.
Four-seat cruiser (Emilia 4 LT) – they won the American Solar Challenge (Cruiser class) last year, and they have written up their design process here, but they have since made substantial improvements to the vehicle, including to the aerodynamics, suspension, battery, and solar panels. There is also an unusual open tail. They shipped their car on the MSC Loretta (as did SER). Based on photographs and the 2017 rating scheme, I would expect their car practicality to score around 75%.
Previously, Onda came 10th at WSC 13; won the ASC 18 Cruiser class; came 10th at Abu Dhabi 15; and came 6th at iESC 16. Their team number (9) is taken from the SS 9, the highway through Bologna, which was once the Roman Via Aemilia (hence also the name of their vehicle).
Monohull challenger (new car: Tokai Challenger) – their new car looks almost identical to the old one, but with optimisations following aerodynamic analysis. They are also using a lithium polymer battery pack instead of lithium-ion, and Sunpower solar cells instead of Panasonic HIT cells this year. They are reporting an unchanged solar cell efficiency of 24.1%, although this seems inconsistent with what Sunpower says. They revealed their car on 3 September.
Two-seat cruiser (thyssenkrupp SunRiser) – Bochum have not built a new WSC car, but have improved their sexy 2-seater SunRiser, which came 3rd in 2015. They also have a solar buggy team. Based on photographs and the 2017 rating scheme, I would expect their car practicality to score around 90%. Their thyssenkrupp SunRiser reached Sydney on the ship Al Bahia on 27 August. In Darwin, they are based at Nightcliff Middle School.
Previously, Bochum came 2nd in the WSC 13 Cruiser class; came 3rd in the WSC 15 Cruiser class; came 2nd in the WSC 17 Cruiser class; came 3rd, 4th, and 5th at iESC 16; came 2nd, 3rd, and 5th in the iESC 18 Cruiser class; came 1st and 7th at Albi Eco 18; and came 1st and 2nd at Albi Eco 19.
Four-seat cruiser (new car: Helia) – they have had motor problems. They revealed their car on 15 August (pic). Based on photographs and the 2017 rating scheme, I would expect their car practicality to score around 60%.
Two-seat cruiser (Investigator Mk 3) – they were planning to improve aerodynamics, reduce weight, and make some other changes. They have taken an unusual approach to the motor. Based on photographs and the 2017 rating scheme, I would expect their car practicality to score around 45%.
Previously, Flinders participated in the WSC 17 Cruiser class.
Monohull GaAs challenger (new car: Unlimited 3.0) – they won the American Solar Challenge last year (with their car Unlimited 2.0), but have built a hot new “bullet car” this year. They revealed their car on 7 August (pic). At 116.8 kg, their car is the lightest in the event.
Monohull challenger (new car: Black Mamba) – they first showed us their shell, which is a unique asymmetric bullet car. They are using glass-free solar panels. They revealed their car on 21 July (pic). Update: sadly, they had a battery fire during the race.
Asymmetric challenger (new car: Tigris) – they revealed their car on Malaysian television on the morning of 20 August. Update: this team has trailered.
Asymmetric GaAs challenger (new car: RED E) – they are already producing regular vlogs (in Dutch), and have also produced an (English) day-in-the-life blog post. Their design is an incredibly tiny GaAs catamaran with shingled solar cells. They developed a MOOC explaining the design of their 2015 car, and there is an online game of their new car. They revealed their car on 21 June (video). They have, once again, run an excellent simulated race. Their Darwin base is at Charles Darwin University. They are using LiFePO4 batteries, which add 20 kg of weight, but have some advantages.
Previously, Twente came 3rd at WSC 13; came 2nd at WSC 15; came 5th at WSC 17; won iESC 16; and came 1st and 2nd at iESC 18. Their team number (21) is a pun and a wish for success in the race (“Twente-One”).
Classic symmetric challenger (Viking) – this year’s car is an improved version of their 2017 car, with better aerodynamics and electronics. In particular, the two “bites” on the side have been filled in. They revealed their car on 29 June (pic). Update: sadly, they are out of the race.
Previously, MDH participated at WSC 17.
Outrigger challenger (new team with car: Heart Three) – their render showed a bullet car, much like Michigan’s 2017 entry, but they have built a car with outriggers (with the associated drag issues). They revealed their car on 11 June (pic).
Two-seat cruiser (Sophie 6s) – their car is a modification of Sophie 6 from 2017. They revealed their car on 6 July (pic). Based on photographs and the 2017 rating scheme, I would expect their car practicality to score around 60%. They were the first team to pass static scrutineering.
Adventure (Arrow1) – because of damage to their Cruiser car during testing, they have transferred to the Adventure class with an older car (which they also raced at iESC 18).
Previously, Arrow came 7th at WSC 13; came 8th at WSC 15; came 3rd in the WSC 17 Cruiser class; came 5th at Abu Dhabi 15; and came 8th at iESC 18. Their team number (30) is the average age of people on the original team.
Asymmetric challenger (SER-3) – they raced this car in South Africa, but have made some improvements. They revealed the car on 10 July, prior to sending it to Australia by sea (on the MSC Loretta with Onda Solare’s car).
Two-seat cruiser (Eos II) – they are building a new car, but will race an upgraded version of their existing one for BWSC 19 (revealing the upgrade on 19 July). Based on photographs and the 2017 rating scheme, I would expect their car practicality to score around 75%. They made a video shortly after arriving in Australia.
Previously, Minnesota came 4th in the WSC 13 Cruiser class; came 5th in the WSC 15 Cruiser class; participated in the WSC 17 Cruiser class; came 2nd at ASC 14; came equal 10th at ASC 16; and came equal 2nd in the ASC 18 Cruiser class. Their team number (35) is derived from the Interstate 35 highway.
Asymmetric challenger (Musoushin) – this high-school team always does very well.
Four-seat cruiser (new car: Stella Era) – their new car has many cool features and a range of 1200 km. They revealed their car on 4 July (video). Based on photographs and the 2017 rating scheme, I would expect their car practicality to score around 90%. Tragically, their solar panel was damaged in transit.
Previously, Eindhoven won the WSC 13 Cruiser class; won the WSC 15 Cruiser class; won the WSC 17 Cruiser class; and came 7th in the iESC 18 Cruiser class. Their team number (40) is the Eindhoven telephone area code.
Asymmetric challenger (new car: MTAA Super Charge 2) – their shell was produced by Sydney Composites. They revealed their car on 12 September.
Previously, ANU participated at WSC 17.
Adventure (SAV) – this time they will tow the trailer that belongs with the car. Based on photographs and the 2017 rating scheme, I would expect their car practicality to score around 60%. Update: this team has been moved to Adventure class, and then trailered.
Adventure (Ardingly Solar Car) – this high-school team came 6th in the iESC Cruiser class, but have upgraded the car since then. Update: this team has been moved to Adventure class, and then trailered.
Four-seat 60-kWh cruiser (Eagle Two) – they have upgraded and repainted their car, and improved the interior. Based on photographs and the 2017 rating scheme, I would expect their car practicality to score around 90%. Update: sadly, they are out of the race.
Previously, Lodz participated in the WSC 15 Cruiser class; participated in the WSC 17 Cruiser class; came 5th at SASOL 16; and won the iESC 18 Cruiser class. Their team number (45) is a tradition since 2015.
Asymmetric challenger (new car: Axelent) – after showing us a rolling test chassis, a body, and a battery, they revealed their car on 30 August (video). Their car suffered damage in a pre-race accident.
Monohull challenger (new car: Horizon Ace) – their car resembles Tokai’s 2017 vehicle. They revealed their car on 6 July (pic).
Three-seat 33-kWh cruiser (new car: STC-3) – they have a unique passengers-behind-driver Cruiser design, which they have tested on the highway. They have received extensive local news coverage in Thailand. They revealed their car on 8 August (video). Based on photographs and the 2017 rating scheme, I would expect their car practicality to score around 45%. Update: this team has trailered.
Outrigger challenger (new team with car: Alfrödull) – their final render resembled the car of the South African NWU team, although the car they built looks slightly different. They showed us a rolling chassis in May. Their shipping date was in July. See their promo video here.
Four-seat 16-kWh cruiser (new car: Tachyon) – they revealed their new car at FSGP. Their average speed at FSGP was 46.3 km/h, compared to 52.8 km/h for Esteban (the leading single-occupant vehicle). This raises some doubts as to whether they can make the WSC on-road target speed of around 75 km/h. Based on photographs and the 2017 rating scheme, I would expect their car practicality to score around 60%.
Four-seat 20-kWh cruiser (Violet) – they have been testing their car on the track. Based on photographs and the 2017 rating scheme, I would expect their car practicality to score around 75%. They also did some testing at Nyngan in Bogan Shire.
Monohull challenger (new car: Viridian) – they have a great-looking bullet car this year. They revealed their car on 24 June (video).
Four-seat cruiser (new car: Sun Shuttle III). They revealed their car on 1 October. Based on their render and the 2017 rating scheme, I would expect their car practicality to score around 45%.
Asymmetric challenger (new car: Man-Se) – they revealed their car on 14 August.
Monohull GaAs challenger (new car: Eagle) – once again they have a sleek and elegantly unique design. There is a good discussion with interior pics here. They use four-wheel steering to get a sailing effect in cross-winds. They revealed their car on 27 June (video).
Previously, Kogakuin came 14th at WSC 13; came 2nd in the WSC 15 Cruiser class; and came 7th at WSC 17. Their team number (88) is multi-faceted (88 is a lucky number in Japanese kanji; 4 wheels looks like 88; and the team garage is in Hachioji city, with ‘hachi’ meaning ‘eight’).
Asymmetric challenger (Éclipse X.1) – they came an excellent 3rd in the ASC, 102 minutes behind Western Sydney, and hope to go even faster with the new battery pack in their modified car. Their improvements are summarised in their winter newsletter. They revealed their car on 10 June (pic). They sent their car via the Panama canal.
Previously, Eclipse came 18th at WSC 13; came 10th at ASC 14; came 8th at ASC 16; came 4th at FSGP 17; and came 3rd at ASC 18. Their team number (92) is a temporary choice (in the ASC they race as 101, and will do so again in 2020).
Two-seat cruiser (new team with car: Priscilla) – their team is a mixture of lecturers and students from five universities across Australia. They tested a model in a wind tunnel. They revealed their car on 17 September. Based on photographs and the 2017 rating scheme, I would expect their car practicality to score around 45%.
This page last updated 13:39 on 14 October 2019 AEDT.
I have been thinking recently about medicine and complexity, as a result of several conversations over many years. In particular, the Cynefin framework developed by Dave Snowden (see diagram below) seems a useful lens to use (this thought is not original to me – see among others, the articles “The Cynefin framework: applying an understanding of complexity to medicine” by Ben Gray and “Cynefin as reference framework to facilitate insight and decision-making in complex contexts of biomedical research” by Gerd Kemperman). I will also refer to two case studies from the book Five Patients by Michael Crichton, which is still quite relevant, in spite of being written in 1969.
The Cynefin framework divides problems into four quadrants: Obvious, Complicated, Complex, and Chaotic. In addition, the domain of Disorder/Confusion reflects problems where there is no clarity about which of the other domains apply. In medicine, this reflects cases where multiple factors are at work – potentially, multiple chronic conditions as well as one or more acute ones. These conditions can exist in all four quadrants. Ben Gray gives the example of a child with a broken arm linked to both a vitamin deficiency and an abusive home environment. Several quite different interventions may be required.
The quadrant of the Obvious applies to conditions with clear cause and effect, where there is a single right answer. According to Dave Snowden, the appropriate response is to sense what is going on, categorise the situation as one on a standard list, and then to respond in the way that people have been trained to do. This response may be trivial (a band-aid, say), or it may involve enormous professional skill. In medicine, much of nursing falls in this quadrant, as does much of surgery.
Michael Crichton’s Five Patients discuses the case of Peter Luchesi, a man admitted to Massachusetts General Hospital during 1969 with a crushed arm and nearly severed hand, as the result of an industrial accident:
“Three inches above the left wrist the forearm had been mashed. Bones stuck out at all angles; reddish areas of muscle with silver fascial coats were exposed in many places. The entire arm about the injury was badly swollen, but the hand was still normal size, although it looked shrunken and atrophic in comparison. The color of the hand was deep blue-gray.
Carefully, Appel picked up the hand, which flopped loosely at the wrist. He checked pulses and found none below the elbow. He touched the fingers of the hand with a pin and asked if Luchesi could feel it; results were confusing, but there appeared to be some loss of sensation. He asked if the patient could move any of his fingers; he could not.
Meanwhile, the orthopedic resident, Dr. Robert Hussey, arrived and examined the hand. He concluded that both bones in the forearm, the radius and ulna, were broken and suggested the hand be elevated; he proceeded to do this.
Outside the door to the room, one of the admitting men stopped Appel. ‘Are you going to take it, or try to keep it?’
‘Hell, we’re going to keep it,’ Appel said. ‘That’s a good hand.’”
Once the surgeons had sensed the problem and categorised it as an arm reconstruction, a team of three surgeons, two nurses, and an anaesthetist (all highly trained in their respective fields) then spent more than 6 hours in the operating theatre, repairing bone, tendons, and blood vessels. Certainly not trivial, but a case of professionals doing what they were trained to do.
The Complicated quadrant is the realm of diagnosis. Information is collected – in medicine, that generally means patient history, blood tests, scans, etc. – and is then subjected to analysis. This identifies the nature of the problem (in an ideal world, at least), which in turn indicates the appropriate response.
Diagnosis by physicians typically searches for the cause of an illness, while diagnosis by nurses typically focuses on severity. This reflects differences in the responses that physicians and nurses have been trained to provide (the triage officer in a modern hospital is typically a nurse).
Decades of work have gone into automating the diagnosis process – initially using statistical analysis, later using expert systems, and most recently using machine learning. At present, the tool of choice is still the human brain.
In general, modern medicine excels when it operates in the Obvious and Complicated quadrants.
The Complex quadrant is the realm of interactions. It is inherently very difficult to deal with, and cause and effect are difficult to disentangle. The paradigm of information collection and analysis fails, because each probe of the system changes it in some way. The best approach is a sequence of experiments, following each probe with a response that seems reasonable, and hoping to find an underlying pattern or a treatment that works. Michael Crichton provides this example:
“Until his admission, John O’Connor, a fifty-year-old railroad dispatcher from Charlestown, was in perfect health. He had never been sick a day in his life.
On the morning of his admission, he awoke early, complaining of vague abdominal pain. He vomited once, bringing up clear material, and had some diarrhea. He went to see his family doctor, who said that he had no fever and his white cell count was normal. He told Mr. O’Connor that it was probably gastroenteritis, and advised him to rest and take paregoric to settle his stomach.
In the afternoon, Mr. O’Connor began to feel warm. He then had two shaking chills. His wife suggested he call his doctor once again, but when Mr. O’Connor went to the phone, he collapsed. At 5 p.m. his wife brought him to the MGH emergency ward, where he was noted to have a temperature of 108 °F [42 °C] and a white count of 37,000 (normal count: 5,000–10,000).
The patient was wildly delirious; it required ten people to hold him down as he thrashed about. He spoke only nonsense words and groans, and did not respond to his name. …”
One difficulty here was that John O’Connor could not speak, and so could not provide information about where he felt pain. He appeared to suffer from septicaemia (blood poisoning) due to a bacterial infection in his gall bladder, urinary tract, GI tract, pericardium, lungs, or some other organ. Antibiotics were given almost immediately, to save his life. These eliminated the bacteria from his blood, but did not tackle the root infection. They also made it difficult to identify the bacteria involved, or to locate the root infection, thus hampering any kind of targeted response. In the end (after 30 days in hospital!) John O’Connor was cured, but the hospital never did locate the original root infection.
Similar problems occur with infants (Michael Crichton notes that “Classically, the fever of unknown origin is a pediatric problem, and classically it is a problem for the same reasons it was a problem with Mr. O’Connor—the patient cannot tell you how he feels or what hurts”). As Kemperman notes, medical treatment of the elderly often also falls in the Complex domain, with multiple interacting chronic conditions, and multiple interacting drug treatments. Medical treatment of mental illness is also Complex, as the brain adapts to one treatment regimen, and the doctor must experiment to find another that stabilises the patient.
Similarly Complex is the day-to-day maintenance of wellness (see the Food and Wellness section below) which often falls outside of mainstream medicine.
The Chaotic quadrant is even more difficult than the Complex one. Things are changing so rapidly that information collection and experimentation are impossible. The only possible response is a dance of acting and reacting, attempting to stabilise the situation enough that it moves from Chaotic to Complex. Emergency medicine generally falls in this quadrant – immediate responses are necessary to stop the patient dying. In the airline industry, the ultimate (and extremely rare) nightmare of total engine failure shortly after takeoff (as in US Airways Flight 1549) sits here too – each second of delay sees gravity take its toll.
Success in the Chaotic domain requires considerable experience. In cases where the problem is a rare one, this experience must be created synthetically using simulation-based training.
Michael Crichton notes that “The hospital is oriented toward curative treatment of established disease at an advanced or critical stage. Increasingly, the hospital population tends to consist of patients with more and more acute illnesses, until even cancer must accept a somewhat secondary position.” There is, however, a need for managing the Complex space of minor variations from wellness, using low-impact forms of treatment, such as variations in diet. Some sections of this field are reasonably well understood, including:
Traditional culture often addresses this space as well. For example, Chinese culture classifies foods as Yin (cooling) or Yang (heaty) – although there is little formal evidence on the validity of this classification.
There remain many unknowns, however, and responses to food are highly individual anyway. There may be a place here for electronic apps that record daily food intake, medicine doses, activities, etc., along with a subjective wellness rating. Time series analysis may be able to find patterns in such data – for example, I might have an increased chance of a migraine two days after eating fish. Once identified, such patterns suggest obvious changes in one’s diet or daily schedule. Other techniques for managing this Complex healthcare space are also urgently needed.
In 2009, I had the privilege of visiting the United States twice (in June and November).
This was the year that saw the launch of the Lunar Reconnaissance Orbiter (which imaged, among other things, the Apollo 11 landing site), the Kepler space telescope (designed to look for exoplanets), the Herschel space observatory (an infrared telescope studying star formation), the Planck spaceprobe (which studied the cosmic microwave background), and the Wide-field Infrared Survey Explorer (an infrared telescope looking for minor planets and star clusters).
More metaphorically, Bitcoin and the programming language Go were also launched. US Airways Flight 1549, on the other hand, was skillfully landed in a river. In archaeology, hoards were discovered in Staffordshire (gold and silver metalwork) and Shrewsbury (Roman coins). Australian Hospital Ship Centaur, torpedoed in 1943, was discovered off the Queensland coast.
Books of 2009 included Wolf Hall by Hilary Mantel (set in 1500–1535; a TV series of 2015), The Windup Girl by Paolo Bacigalupi (dystopian science fiction; Nebula Award winner), and The Maze Runner by James Dashner (young adult dystopian sci-fi; a film of 2014). Books that I later reviewed include The Lassa Ward by Ross Donaldson and God’s Philosophers by James Hannam.
Movies of 2009 included Avatar (rather disappointing), 2012 (a little silly), Angels & Demons (a travesty), Up (Pixar/Disney), Coraline (designed to give children nightmares), District 9 (designed to give adults nightmares), Julie & Julia (a film about cooking), The Imaginarium of Doctor Parnassus (a film about mirrors), and Sherlock Holmes (a lot of fun). On the whole, a good year for films.
In the leadup to the 2019 Bridgestone World Solar Challenge in Australia this October, most cars have been revealed (see my recently updated illustrated list of teams), with JU’s reveal a few days ago (see below), and Tokai’s reveal due in a few hours.
There are now 9 international teams in Australia (more than the number of local teams). Eindhoven (#40), Agoria (#8), and part of Vattenfall (#3) are driving north to Darwin, while Top Dutch (#6) have a workshop in Port Augusta (and living quarters in Quorn).
The chart below shows progress in submitting compulsory design documents for the race. White numbers highlight eight teams with no visible car or no visible travel plans:
Dancing alongside the more serious practitioners of mainstream mathematics are the purveyors of mathematical puzzles and problems. These go back at least as far as Diophantus (c. 200–284), the Alexandrian “father of algebra.” Alcuin of York (c. 735–804) produced a collection of problems that included the the wolf, the goat, and the cabbages (above); the three men who need to cross a river with their sisters; and problems similar to the bird puzzle published by Fibonacci a few centuries later. In more modern times, Martin Gardner (1914–2010) has done more than anyone else to popularise this offshoot of mathematics. It is often called “recreational mathematics,” because people do it for fun (in part because they are not told that it is mathematics).
Particularly popular in recent times have been Sudoku (which is really a network colouring problem in disguise) and the Rubik’s Cube (which illustrates many concepts of group theory, although it was not invented with that in mind). Sudoku puzzles have been printed in more than 600 newspapers worldwide, and more than 20 million copies of Sudoku books have been sold. The Rubik’s Cube has been even more popular: more than 350 million have been sold.
Recreational puzzles may be based on networks, as in Hashi (“Bridges”). They may be based on fitting two-dimensional or three-dimensional shapes together, as in pentominoes or the Soma cube. They may be based on transformations, as in the Rubik’s Cube. They may even be based on arithmetic, as in Fibonacci’s problem of the birds, or the various barrel problems, which go back at least as far as the Middle Ages.
In one barrel problem, two men acquire an 8-gallon barrel of wine, which they wish to divide exactly in half. They have an empty 5-gallon barrel and an empty 3-gallon barrel to assist with this. How can this be done? It is impossible to accurately gauge how much wine is inside a barrel, so that all that the men can do is pour wine from one barrel to another, stopping when one barrel is empty, or the other is full [highlight to show solution → (8, 0, 0) → (3, 5, 0) → (3, 2, 3) → (6, 2, 0) → (6, 0, 2) → (1, 5, 2) → (1, 4, 3) → (4, 4, 0)]. There is a similar problem where the barrel sizes are 10, 7, and 3.
Apart from being fun, puzzles of this kind have an educational benefit, training people to think. For this reason, Alcuin called his collection of problems Propositiones ad Acuendos Juvenes (Problems to Sharpen the Young). Problems like these may also benefit the elderly – the Alzheimer’s Association in the United States suggests that they may slow the onset of dementia. This is plausible, in that thinking hard boosts blood flow to the brain, and research supports the idea (playing board games and playing musical instruments are even better).