pentomino

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Shapes made of squares

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airplane in flight (plane, aircraft, flying)

7 Puzzling Plane Disappearances

African Americans demonstrating for voting rights in front of the White House as police and others watch, March 12, 1965. One sign reads, "We demand the right to vote everywhere." Voting Rights Act, civil rights.

Timeline of the American Civil Rights Movement

Salem Witch Trials. Photogravure after the painting by Walter McEwen titled - The Witches - circa 1890s.

How Rye Bread May Have Caused the Salem Witch Trials

San Francisco, California/USA-1/18/20: Womens March at Civic Center marching with signs of political protest regarding equality also embracing 2020 presidential candidates and celebrating equality

How Does the U.S. Government Define the Difference Between a Protest and a Riot?

The impeachment trial of Pres. Andrew Johnson, illustration from Frank Leslie's Illustrated Newspaper, March 28, 1868.

What If the President Is Impeached?

Queen Elizabeth II addresses at opening of Parliament. (Date unknown on photo, but may be 1958, the first time the opening of Parliament was filmed.)

All 119 References in “We Didn’t Start the Fire,” Explained

Time zone map with standard time zones and International Date Line

Why Are Some Time Zones 30 Minutes Off Instead of an Hour?

pentomino

game

Learn about this topic in these articles:

polyominoes

In number game: Polyominoes
Somewhat more fascinating are the pentominoes, of which there are exactly 12 forms (Figure 19B). Asymmetrical pieces, which have different shapes when they are flipped over, are counted as one.
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