Draw a closed loop that connects the centres of all cells horizontally or vertically. Wherever two circles are edge-adjacent, the loop must go straight through one, and make a right angle turn in the other.
(Rules and example from WPC 2017 IB)
History of the puzzle
Invented by Anurag Sahay (India) in 2017 as a submission for Puzzle Innovations Contest, a pre-event of WPC 2017.
Appearances in the past WPCs
- WPC 2017/Round 18 by Ashish Kumar