Shade some cells black (leaving the other cells white) so that the grid is divided into non-overlapping regions; cells of the same color are considered in the same region if they are adjacent along edges. The black regions must form the set of given shapes; each shape may be rotated and/or reflected in the final answer. Shapes cannot touch along an edge, but can touch at corners. All white cells must be in the same region.
A cell with a black circle must be shaded and a cell with a white circle must not be shaded.
(Rules and example (5 tetrominoes) from PGP IB)
History of the puzzle
Invented by Palmer Mebane (USA) in 2011. The first puzzle by him can be seen here.