Pentominoes (575)

Variants:
- With two grids: Place the twelve pentominoes into the two grids so that they do not touch each other, not even diagonally. (Each pentomino should appear in only one of the two grids.) Numbers below and to the right indicate the number of cells used by the pentominoes in the respective row and column. Pentominoes may be rotated and reflected. Cells marked with an × cannot be occupied with a pentomino.
- With number of different pentominoes: Place the twelve pentominoes (tetrominoes in the example) into the grid so that they do not touch each other, not even diagonally. Numbers above and to the left indicate the number of cells used by the pentominoes; numbers below and to the right indicate the number of pentominoes that appear in the respective row and column. Pentominoes can be rotated and reflected. Cells marked with an × cannot be occupied with a pentomino.
- No 2x2 empty cells: Place 2 sets of pentominoes in the grid. Two pentominoes may only touch each other diagonally. Empty cells (with no pentominoes) cannot form 2×2 areas inside the grid. A cell with a letter in it must be part of the pentomino shape normally associated with that letter.
Every pentomino covers exactly one letter.