A saw blade is sharpened at West Fraser Pacific Inland Resources sawmill in Smithers, British Columbia, Canada February 4, 2020. REUTERS/Jesse Winter

A burnt seesaw is seen in a playground following a wildfire at the village of Mati, near Athens, Greece, July 25, 2018. REUTERS/Alkis Konstantinidis

Children are seen playing on the seesaw as they enjoy the New Year's Day celebrations at the Millennium park in Abuja, Nigeria January 1, 2018. REUTERS/Afolabi Sotunde

Youth play on a seesaw at a playground next to the buffer zone, on the Turkish Cypriot northern part of the divided city of Nicosia, Cyprus, January 12, 2017. REUTERS/Yiannis Kourtoglou

Children ride on illuminated seesaws in front of the Brussels former stock exchange building La Bourse as part of the Christmas "Winter Wonders" (Plaisirs d'Hiver, Winter Pret) festivities, including a Christmas market and other events in central Brussels, Belgium, November 26, 2016. Picture taken November 26, 2016. REUTERS/Yves Herman

Visitors interact with a light up seesaw installation in London, Britain October 5, 2016. REUTERS/Neil Hall

Visitors interact with a light up seesaw installation in London, Britain October 5, 2016. REUTERS/Neil Hall

Visitors interact with a light up seesaw installation in London, Britain October 5, 2016. REUTERS/Neil Hall

Visitors interact with a light up seesaw installation in London, Britain October 5, 2016. REUTERS/Neil Hall

Visitors interact with a light up seesaw installation in London, Britain October 5, 2016. REUTERS/Neil Hall

Indigenous Sahrawi girls play on an improvised see-saw at a refugee camp of Boudjdour in Tindouf, southern Algeria March 3, 2016. The UN Secretary-General Ban Ki-moon is scheduled to visit the Sahrawi refugees in south-west Algeria's Tindouf region. REUTERS/Zohra Bensemra TPX IMAGES OF THE DAY

Phu La ethnic minority people play a seesaw balance game, during their new year celebrations by a roadside in Vietnam's northern Si Ma Cai district, March 21, 2015. Picture taken March 21, 2015. REUTERS/Kham

A Palestinian boy plays on a see-saw atop the remains of his house that witnesses said was destroyed during the seven-week Israeli offensive, in the east of Gaza City October 2, 2014. An open-ended ceasefire between Israel and Hamas-led Gaza militants, mediated by Egypt, took effect on August 26 after the seven-week conflict. It called for an indefinite halt to hostilities, the immediate opening of Gaza's blockaded crossings with Israel and Egypt, and a widening of the territory's fishing zone in the Mediterranean. REUTERS/Suhaib Salem (GAZA - Tags: POLITICS CIVIL UNREST SOCIETY)

Palestinian boys play on a makeshift seesaw atop the remains of their house, which witnesses said was destroyed during the seven-week Israeli offensive, in the east of Gaza City October 2, 2014. REUTERS/Suhaib Salem (GAZA - Tags: CIVIL UNREST CONFLICT SOCIETY)

A young nun plays on a seesaw as she awaits the arrival of Pope Francis outside the Sao Joaquim Palace in Rio de Janeiro, July 26, 2013. Pope Francis on Thursday issued the first social manifesto of his young pontificate, telling slum dwellers in Brazil that the world's rich must do much more to wipe out vast inequalities between the haves and the have-nots. REUTERS/Pilar Olivares (BRAZIL - Tags: RELIGION)

A member of the Free Syrian Army walks with his weapon in the background as boys play on a seesaw in a public park in Raqqa province, east Syria May 1, 2013. REUTERS/Hamid Khatib (SYRIA - Tags: CONFLICT POLITICS)

Snow covered seesaws are seen in a park as cold winter temperatures hit Romania in downtown Bucharest December 12, 2012. REUTERS/Bogdan Cristel (ROMANIA - Tags: ENVIRONMENT)

Iraqi children, injured during violence in their country, play in a public park as part of their treatment in Amman January 5, 2012. French aid organization Medecins Sans Frontieres (Doctors Without Borders) organized the visit to the park for Iraqi, Yemeni and Syrian children injured in violent conflicts in their home countries. REUTERS/Ali Jarekji (JORDAN - Tags: CONFLICT)

Children play near relief tents for people left homeless by the earthquake in Ercis, near the eastern Turkish city of Van, October 26, 2011.Turkey struggled to provide shelter on Wednesday to tens of thousands left homeless by the earthquake that killed nearly 500, and rescue teams began taking painful decisions to call off searches for those buried alive. REUTERS/Baz Ratner (TURKEY - Tags: DISASTER ENVIRONMENT)

A swing set sits in a flooded trailer park in Bay St. Louis, Mississippi, as Tropical Storm Lee slowly makes landfall September 3, 2011. Tropical Storm Lee threatened the Louisiana coast on Friday with torrential rains and flooding and shut nearly half of U.S. offshore crude oil production and a third of offshore gas production. REUTERS/Dan Anderson (UNITED STATES - Tags: ENVIRONMENT DISASTER ENERGY BUSINESS)

Anna Wisniewska from Warsaw Stock Exchange looks at the WIG 20 and WIG 40 index in Warsaw July 14, 2011. Emerging stocks seesawed around flat on Thursday while currencies fell against the dollar and euro as fears for the United States' gold-plated credit rating ended the previous session's fragile rally in riskier asset classes. In central Europe, recent below-forecast inflation data is also leading investors to scale down rate rise expectations, fuelling a rally in local bonds but hitting currencies across the region -- the Polish zloty, Hungarian forint and Czech crown are trading just off multi-week lows to the euro. REUTERS/Peter Andrews (POLAND - Tags: POLITICS BUSINESS)

A girl plays on a seesaw at a volcano shelter where her family was evacuated on the outskirts of Pasto, southern Colombia, August 26, 2010. Colombia's Galeras volcano (background) erupted on Wednesday, forcing authorities to order the evacuation of thousands of residents from nearby villages and towns, officials said. Around 8,000 people live in risky areas nearby, but many often refuse to leave their homes after frequent eruptions. REUTERS/Jaime Saldarriaga (COLOMBIA - Tags: DISASTER ENVIRONMENT)

Unemployed youths Chris Gathercole and Craig Main make use of a childrens play area in Aylesbury, southern England September 16, 2009. Britain's jobless rate climbed to its highest in almost 13 years in July and while there were signs the pace of layoffs may be slowing, analysts cautioned dole queues could lengthen for some time yet. REUTERS/ Eddie Keogh (BRITAIN BUSINESS EMPLOYMENT)

Internally displaced children, who fled a military offensive in the Swat valley region, play on a seesaw at the UNHCR (United Nations High Commission for Refugees) Yar Hussain camp in Swabi district, located about 120 km (75 miles) northwest of Pakistan's capital Islamabad on June 30, 2009. REUTERS/Faisal Mahmood (PAKISTAN CONFLICT POLITICS SOCIETY)

A cleaner disinfects facilities at a park in Hong Kong April 30, 2009. The World Health Organization said on Wednesday the world is at the brink of a pandemic, raising its threat level as the swine flu virus spread and killed the first person outside of Mexico, a toddler in Texas. REUTERS/Tyrone Siu (CHINA SOCIETY HEALTH)

Palestinian boys play next to their destroyed house in Jabalya following Israel's 22-day offensive in the Gaza Strip January 26, 2009. Some 1,300 Palestinians, including at least 700 civilians, were killed said Palestinian medical officials during the offensive Israel launched in the Hamas-ruled Gaza Strip with the declared aim of ending cross-border rocket attacks. REUTERS/Suhaib Salem (GAZA)

Investors watch a display at a local share market in the northern Indian city of Chandigarh December 18, 2008. Indian shares were little changed in seesaw trade on Thursday as energy stocks fell with oil trading near four-year lows, while banks climbed on rising expectations for a rate cut. Investors were awaiting inflation data due by noon, which could set the tone for the market later in the day. REUTERS/Ajay Verma (INDIA)

A South Korean performer jumps on a traditional seesaw in central Seoul April 27, 2008. REUTERS/Noh Soon-Taek (SOUTH KOREA)

South Korean performers jump on a traditional seesaw in central Seoul April 27, 2008. REUTERS/Noh Soon-Taek (SOUTH KOREA)

Traders work on the floor of the Brazilian Mercantile and Futures Exchange in Sao Paulo March 20, 2008. Brazil's currency slumped for a second session on Thursday as investors sold off assets linked to it and the stock market seesawed near the unchanged mark after sinking 5 percent the previous session. The Bovespa index of the Sao Paulo Stock Exchange fell 0.3 percent to 58,627.82 points, after tumbling 5.01 percent on Wednesday to close near its weakest in two months. REUTERS/Paulo Whitaker (BRAZIL)

Traders work on the floor of the Brazilian Mercantile and Futures Exchange in Sao Paulo March 20, 2008. Brazil's currency slumped for a second session on Thursday as investors sold off assets linked to it and the stock market seesawed near the unchanged mark after sinking 5 percent the previous session. The Bovespa index of the Sao Paulo Stock Exchange fell 0.3 percent to 58,627.82 points, after tumbling 5.01 percent on Wednesday to close near its weakest in two months. REUTERS/Paulo Whitaker (BRAZIL)

Traders work on the floor of the Brazilian Mercantile and Futures Exchange in Sao Paulo March 20, 2008. Brazil's currency slumped for a second session on Thursday as investors sold off assets linked to it and the stock market seesawed near the unchanged mark after sinking 5 percent the previous session. REUTERS/Paulo Whitaker (BRAZIL)

Traders work on the floor of the Brazilian Mercantile and Futures Exchange in Sao Paulo March 20, 2008. Brazil's currency slumped for a second session on Thursday as investors sold off assets linked to it and the stock market seesawed near the unchanged mark after sinking 5 percent the previous session. REUTERS/Paulo Whitaker (BRAZIL)

Traders work on the floor of the Brazilian Mercantile and Futures Exchange in Sao Paulo March 20, 2008. Brazil's currency slumped for a second session on Thursday as investors sold off assets linked to it and the stock market seesawed near the unchanged mark after sinking 5 percent the previous session. REUTERS/Paulo Whitaker (BRAZIL)

Traders work on the floor of the Brazilian Mercantile and Futures Exchange in Sao Paulo March 20, 2008. Brazil's currency slumped for a second session on Thursday as investors sold off assets linked to it and the stock market seesawed near the unchanged mark after sinking 5 percent the previous session. REUTERS/Paulo Whitaker (BRAZIL)

Children play as their parents queue up for relief at a centre at Maghbazar in the capital Dhaka, August 18, 2007. The death toll from floods rose 536 with 20 more death reported overnight, the health ministry said on Friday. REUTERS/Rafiqur Rahman (BANGLADESH)

A miniature schnauzer named "Little Orange" sits on a seesaw at the Coolbaby dog theme park in Beijing May 20, 2006. The newly opened dog theme park, the first in China's capital, has a playground, a swimming pool, obstacle courses, and also a restaurant specially designed for pets. Not only can pets have meals together with their owners, but the recipes offered are based on nutritional science and tailored for dogs of different breeds, ages and sizes. Raising dogs was banned under the rule of late Chinese leader Mao Zedong as a bourgeois pastime and was only made legal a few years ago once living standards rose with the economy. According to the Chinese lunar calendar, 2006 is the year of the dog. REUTERS/Claro Cortes IV

Tsunami survivors play at a rehabilitation camp in the fishing village of Akkarapettai in Nagapattinam, about 325km (202 miles) from the southern Indian city of Chennai, December 25, 2005. Government and multilateral agencies have pledged more than $7.3 billion in aid for nations hit by the December 26, 2004 earthquake and tsunami in the Indian Ocean, while global private donations amount to more than $5.7 billion. REUTERS/Parth Sanyal

Kashmiri children play with a handmade seesaw at a camp in Muzaffarabad, the capital of Pakistan-administered Kashmir, October 18, 2005. The earthquake killed at least 41,000 in Pakistan and injured 67,000, while in Indian Kashmir a further 1,300 people died. REUTERS/Kimimasa Mayama PP05100221

A Turkish Cypriot girl seesaws next to an U.N. Watch tower in Nicosia April 15, 2005. Turkish Cypriots will to go to the polls on Sunday to elect new president in the northern part of the divided Mediterranean island. REUTERS/Fatih Saribas FS/MAD

A member of the Shanghai Circus is thrown into a chair by a seesaw (not in the picture) during a rehearsal in Seoul September 15, 2004. The Chinese acrobatic team, which was founded in 1951, will present their first exhibition in South Korea from Thursday for two weeks. REUTERS/Kim Kyung-Hoon KKH/TW

North Korean men perform while on a seesaw "Korea Peace Festival" in
South Korea's Cheju Island October 24, 2003. About 190 North Korean
athletes and officials flew to Cheju Island on Thursday via a direct
flight for the "Korea Peace Festival", which is a joint sports and
cultural festival to be held October 23-27 amid tension over North
Korea's nuclear weapons ambitions. REUTERS/Lee Jae-Won

LJW/FA

Brazilians traders negotiate on phones on the floor of the Futures and
Commodities Market in Sao Paulo, February 5, 2003 during a slow trading
day. Brazil's currency drifted lower and stocks seesawed on Wednesday
in listless trade as investors braced for a key speech at the United
Nations that may boost the chances of a U.S.-led war against Iraq.
REUTERS/Paulo Whitaker

PW

Traders work on the floor of the New York Stock Exchange on July 22, 2002.
In heavy trading, the market experienced a seesaw session. The Dow Jones
industrial average closed down 234 points at 7,784. REUTERS/Peter Morgan

PM

Traders work on the floor of the New York Stock Exchange on July 22, 2002.
In heavy trading, the market experienced a seesaw session. In late trading
the Dow Jones industrial average was down 100 points at 7,919. REUTERS/Peter
Morgan

PM/ME

A trader watches a monitor on the floor of the New York Stock Exchange on
July 22, 2002. In heavy trading, the market experienced a seesaw session. In
late trading the Dow Jones industrial average was down 100 points at 7,919.
REUTERS/Peter Morgan

PM/ME

A money dealer holds his head during trading at a Tokyo brokerage house July
11, 2002. The dollar seesawed near its 10-month low versus the yen in Asia
on Thursday as wariness that the Japanese authorities may intervene to prop
up the currency restrained dealers who were tempted to sell.
REUTERS/Toshiyuki Aizawa

TA/JS

Clerk James Bonaccorsi (at front) relays trades from the floor at the Chicago Mercantile Exchange in Chicago, June 27, 2001, as trade activity increased and stocks seesawed back on forth on news that the Fed was lowering interest rates by one quarter point.

SO/HB

Trader Dean S. Norris (trading badge NNN) is in the middle of the frenzy on the trading floor at the Chicago Mercantile Exchange in Chicago, June 27, 2001, as trade activity increased and stocks seesawed back on forth on news that the Fed was lowering interest rates by one quarter point. A zoom lens heightens the look of the activity on the floor.

SO/HB

Trader Curtis H. Skinner works two phones and signals to the trading floor at the Chicago Mercantile Exchange in Chicago, June 27, 2001 as trade activity increased and stocks seesawed back on forth on news that the Fed was lowering interest rates by one quarter point.

SO/HB

Traders watch a monitor on the floor of the New York Stock Exchange on April 4, 2001 as stocks seesawed in early trading. By late morning, the Dow Jones industrial average was up 102 points at 9,588.

PM/SV

A trader pauses on the floor of the New York Stock Exchange on April 4, 2001 as stocks seesawed in early trading. By late morning the Dow Jones industrial average was up 102 points at 9,588.

PM/HB

Traders at work on the floor of the New York Stock Exchange shortly after the opening bell on April 23. Stocks were lower in seesaw trading as investors took profits and shifted money among sectors.

PM/SV/ME

Traders on the floor of the New York Stock Exchange shortly after the opening bell April 23. Stocks were lower in seesaw trading as investors took profits and shifted money among sectors. By late morning, the Dow Jones industrial average was down 72.16 points at 10,655.02.

PM/SV/ME

Romanian policemen watch thousands of wood industry workers carrying seesaws in hand during a rally March 16 staged for pay rises and against uncontrolled deforestation in Romania. Romania's forest area dropped by 5,000 hectares to 6.2 million hectars in 1994