- Sir Roger Penrose demonstrates the extraordinary moiré patterns produced by overlaying and rotating two identical, repeating patterns. As the two patterns overlapped and rotated they interfere with each other to produce tertiary patterns.
- Chicago (Wikipedia)
Chicago (/ʃɪˈkɑːɡoʊ/ shih-KAH-goh, locally also /ʃɪˈkɔːɡoʊ/ shih-KAW-goh; Miami-Illinois: Shikaakwa; Ojibwe: Zhigaagong) is the most populous city in the U.S. state of Illinois and the third-most populous in the United States after New York City and Los Angeles. With a population of 2,746,388 in the 2020 census, it is also the most populous city in the Midwest. As the seat of Cook County, the second-most populous county in the U.S., Chicago is the center of the Chicago metropolitan area.