> "So often we read of very large companies riding rough-shod over small businesses or individuals," said David Bradley, director of Pentaplex. "But when it comes to the population of Great Britain being invited by a multi-national to wipe their bottoms on what appears to be the work of a Knight of the Realm without his permission, then a last stand must be made."
http://krazydad.com/slitherlink/sfiles/sl_penrose_b001.pdf
Years ago, I sought (and received) permission from Penrose to use his tiling on these puzzles.
Play it here: http://www.chiark.greenend.org.uk/~sgtatham/puzzles/js/loopy...
You can play penrose style puzzles by selecting the type in the furthest right drop down menu.
(beware, select custom and choose easy mode, becuase hard mode is hard)