- 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.
- Arden Hills, Minnesota (Wikipedia)
Arden Hills is a city in Ramsey County, Minnesota, United States. The population was 9,552 at the 2010 census. Bethel University and Seminary is located in the city of Arden Hills. Also, the campus of University of Northwestern – St. Paul straddles the Arden Hills – Roseville border. The headquarters of Land O’Lakes and Catholic United Financial, a fraternal benefit society, are located there as well.