Place the twelve given pentominoes into the grid so that they do not touch each other, not even diagonally. Each outlined region contains exactly one pentomino, and no pentomino is in more than one region. Pentominoes can be rotated and reflected.
(Rules from PGP IB, example (tetrominoes) from Polish Nationals 2014)
- Instead of 12 pentominoes, this puzzle can be generalised to placing a given set of polyominoes. The extreme is Regional Hexominoes from WPC 2019/Round 10, in which you literally had to place all 35 hexominoes into the grid.
- In a puzzle from WPC 2015/Round 7, instead of one, three pentominoes of three different colours were placed in a region. Pentominoes with different colours could touch each other but couldn't occupy the same cell. Pentominoes of the same colour followed the same rules as above.
History of the puzzle
Most likely first appeared on 2005 Japanese "Internet Qualifier. Its author is currently unknown.
Appearances in the past WPCs
- WPC 2019/Round 10 (Hexominoes) by Sebastian Matschke
- WPC 2018/Round 11 (7 Tetrominoes, Pentominoes) by Jiří Hrdina
- WPC 2016/Round 17 by Matúš Demiger
- WPC 2015/Round 7 by Tawan Sunathvanichkul