Sumatran tiger cubs play around a chalkboard placed during the annual stocktake at ZSL London Zoo in London, Britain, January 3, 2023. REUTERS/Toby Melville 

A chalkboard sign encouraging people to vote in the midterm elections hangs in Milwaukee, Wisconsin, U.S. November 8, 2022. REUTERS/Daniel Steinle 

A boy shows his slate chalkboard inside a parked bus run by TejasAsia, an NGO using "Hope" buses as mobile classrooms for children living in slums, on the floodplains of the Yamuna river in New Delhi, India August 9, 2021. Picture taken August 9, 2021. REUTERS/Anushree Fadnavis 

Radhika, 9, hands out a slate chalkboard to a teacher inside a parked bus run by TejasAsia, an NGO using "Hope" buses as mobile classrooms for children living in slums, near the Tughlaqabad fort in New Delhi, India August 6, 2021. Picture taken August 6, 2021. REUTERS/Anushree Fadnavis 

Slate chalkboards lie in the seats of a parked bus run by TejasAsia, an NGO using "Hope" buses as mobile classrooms for children living in slums, near the Tughlaqabad Fort in New Delhi, India August 6, 2021. Picture taken August 6, 2021. REUTERS/Anushree Fadnavis 

Official tallies the ballots on a chalkboard during the presidential election in Abidjan, Ivory Coast October 31, 2020. REUTERS/Luc Gnago 

Small toy figures are placed on a chalkboard near "Social distancing" words printed on paper in this illustration taken May 27, 2020. REUTERS/Dado Ruvic/Illustration 

Small toy figures are placed on a chalkboard near "Social distancing" words printed on paper in this illustration taken May 27, 2020. REUTERS/Dado Ruvic/Illustration 

Small toy figures are placed on a chalkboard near "Social distancing - COVID-19" words printed on paper in this illustration taken May 27, 2020. REUTERS/Dado Ruvic/Illustration 

Small toy figures are placed on a chalkboard near "Social distancing - COVID-19" words printed on paper in this illustration taken May 27, 2020. REUTERS/Dado Ruvic/Illustration 

Small toy figures are placed on a chalkboard near "Social distancing - COVID-19" words printed on paper in this illustration taken May 27, 2020. REUTERS/Dado Ruvic/Illustration 

Small toy figures are placed on a chalkboard near "Social distancing" printed words in this illustration taken May 27, 2020. REUTERS/Dado Ruvic/Illustration 

A pupil, wearing a protective mask, writes on a classroom chalkboard at the Merlan school of Paillet during the reopening of schools, as the lockdown due to coronavirus disease (COVID-19) is eased, in Abidjan, Ivory Coast May 25, 2020. REUTERS/Luc Gnago 

The chalkboard is seen inside closed "Le Bistrot d'a cote Flaubert" restaurant, amid the coronavirus disease (COVID-19) outbreak, in Paris, France, May 22, 2020. REUTERS/Christian Hartmann 

A sign has been modified to read "I will be grateful for Covid ending" amid the coronavirus disease (COVID-19) outbreak in Brattleboro, Vermont, U.S., April 19, 2020. REUTERS/Brian Snyder 

A sign has been modified to read "I will be grateful for Covid ending" amid the coronavirus disease (COVID-19) outbreak in Brattleboro, Vermont, U.S., April 19, 2020. REUTERS/Brian Snyder 

A message is seen written on a chalkboard in the window of The Prince Harry pub in Windsor while the spread of the coronavirus disease (COVID-19) continues, Windsor, Britain, April 7, 2020. REUTERS/Andrew Couldridge 

A message is seen written on a chalkboard in the window of the Prince Harry pub in Windsor while the spread of the coronavirus disease (COVID-19) continues, Windsor, Britain, April 7, 2020. REUTERS/Andrew Couldridge 

A desk is seen in an empty classroom of a school, after Haiti's government declared a state of emergency over the coronavirus disease (COVID-19) outbreak, closing the country's borders and imposing a curfew upon detecting the first two cases of infection, in Port-au-Prince, Haiti March 20, 2020. REUTERS/Andres Martinez Casares 

A blackboard, with an old train schedule written on it, hangs at the decommissioned Voi train station in Voi, Kenya, November 13, 2019. REUTERS/Baz Ratner SEARCH "MOMBASA-NAIROBI TRAIN" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES. 

A combo shows unemployed people posing in front of a chalkboard with their qualifications during a job fair in Chinchwad, India, February 7, 2019. (Top L-R) Rahul Dandwate, a 26-year-old Bachelor of Engineering (B.E.) graduate who has been unemployed for one year, Tejaswini Shelake, a 23-year-old Bachelor of Engineering (B.E.) graduate who has been unemployed for four months and Mandar Gosavi, a 38-year-old Bachelor of Commerce graduate who has been unemployed for three months. (Center L-R) Ashwani Khabale, a 21-year-old Bachelor of Technology who has been unemployed for one year, Vikas Kamble, a 27-year-old fitter who has been unemployed for six months and Kajal Ithape, a 25-year-old Master of Commerce (M. Com.) who has been unemployed for six months. (Bottom L-R) Pankaj Kumbhakarn, a 27-year-old Master of Computer Science graduate who has been unemployed for one year, Gayatri, a 24-year-old Master of Engineering graduate who has been unemployed for four months and Santosh Gurav, a 27-year-old Bachelor of Technology who has been unemployed for six months. Picture taken February 7, 2019. To match Insight INDIA-ELECTION/JOBS-ENGINEERS. REUTERS/Danish Siddiqui 

A girl holds her chalkboard as she arrives to attend lessons at the evening school in Ouakam neighbourhood, Dakar, Senegal January 16, 2019. Picture taken January 16, 2019. REUTERS/Zohra Bensemra 

Fresh fish prices are displayed in a fishmongers shop in London, Britain, October 30, 2018. REUTERS/Russell Boyce 

A sign is seen in front of bottles of wine being sold at a retail store at Sydney Airport in Sydney, Australia, October 17, 2018. REUTERS/Phil Noble 

Messages are left on a chalkboard wall ahead of the one-year anniversary of 2017 Charlottesville "Unite the Right" protests, in Charlottesville, Virginia, U.S., August 10, 2018. REUTERS/Jim Urquhart 

A woman writes on a chalkboard wall ahead of the one-year anniversary of 2017 Charlottesville "Unite the Right" protests, in Charlottesville, Virginia, U.S., August 10, 2018. REUTERS/Jim Urquhart 

A woman walks past a chalkboard wall ahead of the one-year anniversary of 2017 Charlottesville "Unite the Right" protests, in Charlottesville, Virginia, U.S., August 10, 2018. REUTERS/Jim Urquhart 

A woman walks past a chalkboard wall ahead of the one-year anniversary of 2017 Charlottesville "Unite the Right" protests, in Charlottesville, Virginia, U.S., August 10, 2018. REUTERS/Jim Urquhart 

Children write on a chalkboard in a hallway of the abandoned Prestes Maia textile factory occupied by a homeless movement in downtown Sao Paulo, Brazil May 12, 2018. The roughly 20-storey tall building is the largest vertical occupation in Latin America. The residents refer to themselves as the Prestes Maia Occupation. REUTERS/Nacho Doce SEARCH "BRAZIL HOMELESS" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES. 

A classroom is seen at the Government Girls Science and Technical college in Dapchi, the northeastern state of Yobe, Nigeria, February 27, 2018.REUTERS/Afolabi Sotunde SEARCH "DAPCHI PARENTS" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES. 

A chalkboard pointing to a FEMA office is shown in the aftermath of tropical storm Harvey in Wharton, Texas, U.S., September 6, 2017. REUTERS/Mike Blake 

Messages of support to Barcelona are written on a chalkboard in Borough Market in London, Britain August 18, 2017. REUTERS/Neil Hall 

A chalkboard with messages written on July 5, 2017, is stained with mud inside Masue elementary school, where local residents were temporary evacuated to, at Haki district in Asakura, Fukuoka Prefecture, Japan July 7, 2017. REUTERS/Issei Kato 

A voter leaves a polling station for the Schleswig Holstein regional state elections, in Kiel, Germany, May 7, 2017. REUTERS/Fabian Bimmer 

A chalkboard used to show the daily menu stands by the pool of a hotel in Banjul, Gambia January 19, 2017. REUTERS/Afolabi Sotunde 

A child wipes off a chalkboard as others look out the window as they wait for Prince Harry during his official visit to Codrington, Barbuda, November 22, 2016. REUTERS/Carlo Allegri 

A hand drawn Harley-Davidson picture is seen on a chalkboard in their head office in Singapore October 13, 2016. REUTERS/Edgar Su 

A blackboard keeps the date of the latest school day before Hurricane Matthew at the school Inmaculate Conception in Les Anglais, Haiti, October 12, 2016. REUTERS/Andres Martinez Casares 

Clarice Raphael rests on a bed at school Inmaculate Conception after Hurricane Matthew in Les Anglais, Haiti, October 12, 2016. REUTERS/Andres Martinez Casares 

A chalkboard sign informs visitors to "Buy British" as they enter Shakespeare's Corner Shopppe, a store catering to all things British from food to tea pots, in San Diego, California, U.S. June 28, 2016. REUTERS/Mike Blake

Gabriel Morris writes on a chalkboard during the "Politicon" convention in Pasadena, California, U.S. June 25, 2016. REUTERS/Patrick T. Fallon 

A chalkboard advertises a viewing event at "The Churchill Tavern", a British theme bar, on the day where Britain votes whether or not to remain in the European Union in the Manhattan borough of New York, U.S., June 23, 2016. REUTERS/Andrew Kelly

Children pose next to a chalkboard advertising a Brexit viewing event at "The Churchill Tavern", a British theme bar, on the day where Britain votes whether or not to remain in the European Union in the Manhattan borough of New York, U.S., June 23, 2016. REUTERS/Andrew Kelly

Britain's Kate, the Duchess of Cambridge visits the newly opened "Magic Garden" at Hampton Court Palace, west of London, Britain, May 4, 2016. REUTERS/Richard Pohle/Pool 

Britain's Kate, the Duchess of Cambridge visits the newly opened "Magic Garden" at Hampton Court Palace, west of London, Britain, May 4, 2016. REUTERS/Richard Pohle/Pool 

Britain's Kate, the Duchess of Cambridge visits the newly opened "Magic Garden" at Hampton Court Palace, west of London, Britain, May 4, 2016. REUTERS/Richard Pohle/Pool 

Britain's Kate, the Duchess of Cambridge visits the newly opened "Magic Garden" at Hampton Court Palace, west of London, Britain, May 4, 2016. REUTERS/Richard Pohle/Pool 

A board shows a selection of hedgehogs for sale at the Harry hedgehog cafe in Tokyo, Japan, April 5, 2016. In a new animal-themed cafe, 20 to 30 hedgehogs of different breeds scrabble and snooze in glass tanks in Tokyo's Roppongi entertainment district. Customers have been queuing to play with the prickly mammals, which have long been sold in Japan as pets. The cafe's name Harry alludes to the Japanese word for hedgehog, harinezumi. Prices are shown in yen. REUTERS/Thomas Peter SEARCH "HEDGEHOG THOMAS" FOR THIS STORY. SEARCH "THE WIDER IMAGE" FOR ALL STORIES

Students wear Syrian Arab Red Crescent uniforms during a vaccine campaign at a school in the rebel held Douma neighborhood of Damascus, Syria March 21, 2016. REUTERS/Bassam Khabieh 

Chalk is placed on a blackboard at a floating school in the Makoko fishing community on the Lagos Lagoon, Nigeria February 29, 2016. In Makoko, a sprawling slum of Nigeria's megacity Lagos, a floating school capable of holding up to a hundred pupils has since November brought free education to the waterways known as the Venice of Lagos. It offers the chance of social mobility for youngsters who, like most of the city's 21 million inhabitants, lack a reliable electricity and water supply and whose water-based way of life is threatened by climate change as well as rapid urbanisation. REUTERS/Akintunde Akinleye SEARCH "THE WIDER IMAGE" FOR ALL STORIES TPX IMAGES OF THE DAY TPX IMAGES OF THE DAY

An indigenous Sahrawi teacher attends a class at a school in a refugee camp of Boudjdour in Tindouf, southern Algeria March 3, 2016. UN Secretary General Ban Ki-moon is scheduled to visit the Sahrawi refugees in south-west Algeria's Tindouf region. REUTERS/Zohra Bensemra 

A boy looks around as portraits of North Korea's founder Kim Il Sung (L) and his son and late leader Kim Jong Il hang on the wall of a mock North Korean classroom at the Unification Observation Platform, near the demilitarized zone (DMZ) which separates the two Koreas, in Paju, South Korea, January 7, 2016. REUTERS/Kim Hong-Ji TPX IMAGES OF THE DAY

Peer 1 clients stand silently facing a wall during a monad self-discovery meditation session with a chalkboard that reads, "You can only blame yourself for your actions" at Peer 1 in Denver July 22, 2014. Peer 1 is a drug and alcohol rehabilitation programme for men, many having spent years in and out of prison, in Denver, Colorado. The men have often tried and failed over and over to turn their life around. With histories of abuse as children and living on the streets, they come to Peer 1 hoping to turn away from addiction and crime, to rebuild their lives and learn how to integrate into society. Treatment includes family group therapy, meditation and trust-building exercises. REUTERS/Rick Wilking TPX IMAGES OF THE DAY PICTURE 17 OF 26 FOR WIDER IMAGE STORY "PEER 1: PRISON, DEATH OR RECOVERY". SEARCH "PEER WILKING" FOR ALL IMAGES 

U.S. President Barack Obama's daughters Malia (R) and Sasha (L) depart the Upshur Street Books after visting the store to buy books with their father, in Washington, November 28, 2015. Today is Small Business Saturday, which was started to encourage shoppers to buy locally and from brick-and-mortar stores, and serves as a counterpoint to the traditionally busy shopping days of Black Friday and Cyber Monday after the Thanksgiving holiday. REUTERS/Mike Theiler 

A man solicits bets for the horse races while standing next to a chalkboard at the Far Hills Race Day at Moorland Farms in Far Hills, New Jersey, October 17, 2015. Young locals in New Jersey catch up with friends from school and college days at the Far Hills Race Day, which started as a fox-hunting event in the early 1900s. Many racegoers first went to the Hunt, as it's known locally, as children, but nowadays it's an alcohol-fuelled party for them. Makeshift bars are set up in cars, with the horses' efforts on the turf sometimes a backdrop to the main event. REUTERS/Stephanie KeithPICTURE 18 OF 20 FOR WIDER IMAGE STORY "NEW JERSEY: A DAY AT THE RACES"SEARCH "FAR HILLS RACES" FOR ALL IMAGES

A man teaches students at a school in Kababiyan refugee camp in Peshawar, Pakistan, October 6, 2015. Aid programmes for some of the 2.5 million Afghan refugees in Pakistan are being slashed amid the worst funding shortfall for a generation, as the European and Syrian migrant crisis uses up cash and dominates headlines, United Nations officials said. Picture taken October 6, 2015. REUTERS/Faisal Mahmood

Afghan girls study at an open area, founded by Bangladesh Rural Advancement Committee (BRAC), outside Jalalabad city, Afghanistan September 16, 2015. REUTERS/Parwiz TPX IMAGES OF THE DAY

Afghan girls study at an open area, founded by Bangladesh Rural Advancement Committee (BRAC), outside Jalalabad city, Afghanistan September 16, 2015. REUTERS/Parwiz 

Students work at the Agustin Ferreira farm school near Minas city, in the northeast of Montevideo, September 15, 2015. The school has 12 students aged 4 to 11, with only one teacher, and incorporates activities such as milking a cow, planting vegetables and cooking to improve the education of the children. REUTERS/Andres Stapff 

Sarah Nasira, 12, leads her classmates as they revise their class work without a teacher on the second week of a national teachers' strike, at Olympic Primary School in Kenya's capital Nairobi, September 9, 2015. The Kenya National Union of Teachers (KNUT) wants the Teachers Service Commission (TSC) to honour the 50-60 percent salary increment ordered by the Supreme Court in August, local media reported. REUTERS/Thomas Mukoya TPX IMAGES OF THE DAY