Survo puzzles: www.survo.fi/puzzles --------------------------------------- Copyright (c) Survo Systems 2006-2012 The easiest way to solve these three problems may be using a Java Applet http://www.survo.fi/swap/puzzles.html based on the swapping method. Survo puzzle 291/2012 (70) #443-30404 A B C D 1 15 * * * 45 2 * * * 8 51 3 * 2 * * 12 4 * * 9 * 28 46 32 39 19 Survo puzzle 292/2012 (440) #443-55466 A B C D 1 3 * * * 23 2 * * * * 14 3 * * * * 54 4 * * * * 45 22 37 46 31 Survo puzzle 293/2012 (1500) #443-81812 A B C D 1 * * * * 41 2 * * * * 51 3 * * * * 19 4 * * * * 25 38 14 50 34