Rules: Shade some cells to form a continuous, connected wall (that is, a single polyomino) containing no 2×2 squares of shaded cells. Clue cells can’t be shaded. A clue tells the sizes of groups of shaded cells in the eight cells surrounding the clue (compare this to Minesweeper, where the clue would only tell the number of shaded cells around the clue, but not the grouping).
‘?’-clues stand for any nonzero number, unless otherwise noted.
This puzzle type was invented by Serkan Yürekli.