An African Penguin holds a Valentine's Day card at the California Academy of Sciences on February 13, 2013 in San Francisco, California. In honor of Valentine's Day, the colony of African Penguins at the California Academy of Sciences received heart-shaped red valentines with hand written messages from Academy visitors. (Photo by Justin Sullivan)
Taras Mychalewych, 75, poses for a portrait with his vaccination card after receiving his coronavirus disease (COVID-19) vaccine at a rural vaccination site in Columbus, New Mexico, U.S., April 16, 2021. (Photo by Paul Ratje/Reuters)
House Minority Leader Kevin McCarthy (R-CA) and U.S. President Donald Trump watch a woman carry a card announcing the rounds during a mixed martial arts fight in Madison Square Garden in New York, New York, U.S., November 2, 2019. (Photo by Joshua Roberts/Reuters)
Klemens Torggler's door is an invention based on rotating squares, The special construction makes it possible to move the door sideways without the use of tracks. This technical trick opens up new applications for the door.