Draw a closed loop passing through the centres of cells horizontally or vertically. The loop must cross itself only at cells containing a + sign. Cells with triangles in them reflect the loop at right angles, and all cells containing triangles must be visited by the loop. Numbered triangles indicate the total number of cells, including the triangle's cell, that the loop segments travel horizontally and vertically before changing direction.
(Rules and example from WPC 2017 IB)
History of the puzzle
First appeared on Nikoli volume 106 (2004).
Appearances in the past WPCs
- WPC 2017/Round 16 by Ashish Kumar