From WPC unofficial wiki


Draw a single loop consisting of alternating horizontal and vertical line segments. All cells where the loop makes a turn and both segments are of equal length are marked with numbers showing the length of those segments.

(Rules from WPC 2015 IB, example by EctoPlasma)

History of the puzzle[edit]

Probably first appeared on WPC 2015/Round 4. Author of the puzzle was Svetlozar Stefanov (Bulgaria).

Appearances in the past WPCs[edit]