Windows
Channel: Клуб ценителей головоломок Диоген
Date: 2017-10-10

Shade exactly two cells in each of the thickly outlined 2x2 regions, i.e. the Windows. Shaded cells must form a single connected area. All white cells must be connected horizontally or vertically through other white cells to an edge of the grid. No 2x2 area can contain all shaded cells or all white cells.