A Palestinian man walks down snow-covered stairs after Friday prayers near the Dome of the Rock on the compound known to Muslims as Noble Sanctuary and to Jews as Temple Mount, in Jerusalem's Old City February 20, 2015. Snow covered Jerusalem and mountainous areas of Israel early Friday morning and the education ministry closed schools for the day. (Photo by Ammar Awad/Reuters)

A Sponge Bob Square Pants character is helped up a flight of stairs during the 2013 London Toy Fair at Olympia Exhibition Centre on January 22, 2013 in London, England. The annual fair which is organised by the British Toy and Hobby Association, brings together toy manufacturers and retailers from around the world. (Photo by Dan Kitwood)

A participant takes photographs of his friend while climbing up the stairs during Sky Run, a vertical marathon event, held in the 123-story Lotte World Tower, in Seoul, South Korea on April 22, 2023. (Photo by Kim Soo-hyeon/Reuters)

Only with a pencil, ruler and protractor, without the help of a computer, Venezuelan artist Rafael Araujo creates complex fields of three dimensional space where butterflies come to life and shells rise from mathematical spirals.

In this May 14, 2016 photo, children wearing their school backpacks climb on a cliff using a bamboo ladder on their way home from school in Zhaojue county, southwest China's Sichuan province. A village in China's mountainous west where schoolchildren must climb an 800-meter (2,625-foot)-high bamboo ladder secured to a sheer cliff face may get a set of steel stairs to improve it's safety. (Photo by Chinatopix via AP Photo)

Blind and visually impaired Palestinian students walk down the stairs at a school, where they are taught English through song and music, at a school in the West Bank city of Hebron March 2, 2016. Palestinian students at a school for the blind in the West Bank are learning English through song, a welcome departure from using braille and memorising grammar rules. While students are delighted with the change, some parents in the religiously conservative town of Hebron are concerned that using music in the classroom jars with Islamic tradition. (Photo by Ammar Awad/Reuters)

A 20 metre high spiral staircase in a tower used as an emergency exit, is seen inside a Federal Reserve bank (Bundesbank) bunker, prior to the bunker's official opening to the public in Cochem, Germany, March 18, 2016. West Germany's Central Bank (Deutsche Bundesbank) stored some 20 billion German marks of emergency notes in two underground bunkers, one in Frankfurt the other in Cochem, between 1964-1988 during the cold war. (Photo by Kai Pfaffenbach/Reuters)

Children play underneath Jacaranda trees lining a street in the capital Harare, Zimbabwe, Friday, October 11, 2019. Zimbabwe now has the world's second highest inflation after Venezuela, according to International Monetary Fund figures. The economy has been on a downward spiral for more than a year as hopes fade that Mugabe's successor and former deputy, President Emmerson Mnangagwa, will deliver on his promises of prosperity. (Photo by Tsvangirayi Mukwazhi/AP Photo)