Shade cells on the grid to form a single orthogonal region.
2x2s of shaded cells are disallowed.
Any cell with only one shaded orthogonal neighbor must border the edge of the board.
Every unshaded region must be rectangular and will have a number(s) in it indicating its dimensions: a 2x2 would be clued with a 2 or two 2s; a 1x3 would be clued with a 1 and a 3.
Two cells that both touch the border cannot be orthogonally adjacent.