Draw a closed loop passing through centres of all cells horizontally or vertically. It can enter and exit any region only once.
(Rules and example from WPC 2017 IB)
History of the puzzle
First appeared on 2008 German Nationals. Author of the puzzle was Hartmut Seeber (Germany). The original name "Rundweg en gros" means "loop in bulk" in German.
The name of this article is based on a puzzle from WPC 2017.
See also Double Back, an independent puzzle similar to this.
Appearances in the past WPCs
- WPC 2017/Round 12 by Amit Sowani