# New in *MathWorld* -- December
2021

### Friday December 31, 2021

- Graph Join (modified)
- Matchstick Graph (modified)
- Projective Plane Crossing Number (modified)
- Unit-Distance Graph (modified)
- Windmill Graph (modified)

### Thursday December 30, 2021

- Klein Bottle Crossing Number (modified)
- Projective Plane Crossing Number (modified)

### Wednesday December 29, 2021

### Monday December 27, 2021

- Vertex Contraction (modified)

### Wednesday December 22, 2021

- Bislit Cube (modified)
- Blanuša Snarks (modified)
- Logic (modified)
- Rule

### Tuesday December 21, 2021

- Code (modified)
- Mathematics (modified)

### Saturday December 18, 2021

- Integer Sequence Primes (modified)
- NSW Number (modified)
- Pell Number (modified)

### Friday December 17, 2021

- Articulation Vertex (modified)
- Doyle Graph (modified)

### Monday December 13, 2021

- Integer Sequence Primes (modified)
- Smarandache Prime (modified)
- Zebra Graph (modified)

### Thursday December 9, 2021

- Block (modified)
- Camel Graph (modified)
- Flower Snark (modified)
- Giraffe Graph (modified)
- Goldberg Graph
- Goldberg Snark
- Tietze's Graph (modified)
- Zebra Graph (modified)

### Wednesday December 8, 2021

- Snark (modified)
- Weak Snark

### Tuesday December 7, 2021

- Biconnected Graph (modified)
- Camel Graph (modified)
- Giraffe Graph (modified)
- Zebra Graph (modified)

### Friday December 3, 2021

- Articulation Vertex (modified)

### Thursday December 2, 2021

- Block (modified)

### Wednesday December 1, 2021

- Antelope Graph (modified)
- Fairy Chess (modified)
- Giraffe Graph (modified)
- Leaper Graph (modified)
- Zebra Graph (modified)

[ 2024 ▪ 2023 ▪ 2022 ▪ 2021 ▪ 2020 ▪ 2019 ▪ 2018 ▪ 2017 ▪ 2016 ▪ 2015 ▪ 2014 ▪ 2013 ▪ 2012 ▪ 2011 ▪ 2010 ▪ 2009 ▪ 2008 ▪ 2007 ▪ 2006 ▪ 2005 ▪ 2004 ▪ 2003 ▪ 2002 ▪ 2001 ▪ 2000 ▪ 1999 ]