Survo puzzles: www.survo.fi/puzzles --------------------------------------- Copyright (c) Survo Systems 2006-2011 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 231/2011 (180) #443-68844 A B C D 1 * 10 * * 28 2 * * * 8 44 3 * * * * 40 4 * * * * 24 53 47 14 22 Survo puzzle 232/2011 (350) #443-93390 A B C D 1 * * * * 14 2 * 12 * * 38 3 * * * * 26 4 * * * * 58 22 39 32 43 Survo puzzle 233/2011 (450) #443-21208 A B C D 1 3 * * * 21 2 * * * * 56 3 * * * * 15 4 * * * * 44 24 30 38 44