Shade in tetrominoes such that the black cells are all connected to each
other through their edges, and no 2x2 cell area within the grid
contains all black cells. No two congruent tetrominoes may share an
edge, even if they are rotated or reflected versions of each other.
Numbers to the left of a row or above a column represent the groups of
consecutive black cells which are in that row or column. For example, a
clue of "3" means the row or column has three consecutive black cells,
and a clue of "3 1" means that the row or column has a group of three
consecutive black cells followed by a single black cell, separated by at
least one white cell. A question mark (?) represents a group of
consecutive black cells whose size is unknown; an asterisk (*)
represents any number of unknown groups of black cells, including none at all.