Possible placements of the Battleships fleet is given. Ships are oriented horizontally or vertically and they don't touch each other, not even diagonally. There cannot be any ship segments on water marks.
(Rules and example (standard fleet of size 3) from 2010 24hPC IB)
History of the puzzleEdit
Later, "Retrograde Penta" appeared on WPC 2003/Part 2. Its author is currently unknown.