Shade some cells in the grid. Shaded cells cannot touch each other orthogonally. All unshaded cells must be orthogonally interconnected. Unshaded cells cannot form a 2x2 square. Cells with circles cannot be shaded.
A number indicates how many other numbers or circles can be reached from that cell by passing only orthogonally through empty unshaded cells (it cannot pass through a shaded cell nor a cell with a number/circle).
(Rules and example from WPC 2016 IB)
History of the puzzle
First appeared on WPC 2016/Round 11, an "innovative" round. The author of the puzzle was Matej Uher (Slovakia).
Appearances in the past WPCs
- WPC 2016/Round 11 by Matej Uher