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 267/2012 (100) #443-22234 A B C D 1 7 * * 2 26 2 * * 10 * 20 3 * * * * 54 4 * 8 * * 36 37 27 53 19 Survo puzzle 268/2012 (540) #443-82616 A B C D 1 * * * * 43 2 * * * * 11 3 * * * * 57 4 7 * * * 25 37 32 41 26 Survo puzzle 269/2012 (920) #443-74130 A B C D 1 * * * * 16 2 * * * * 40 3 * * * * 53 4 * * * * 27 16 32 40 48