Perplexing Sudoku-by5 Logic Puzzles (Vol 1) 
 Chapter 4: Twenty Perplexing (DiffLev 48-50) Sudoku-by5 Puzzles (numbers 21-40) 
 
-  Step-by-step instructions for solving  Puzzle 21, (261/369)   Diff: 48/9333.5211.2325.9999.9971.12D3.4537.7995+
 -  Step-by-step instructions for solving  Puzzle 22, (266/369)   Diff: 48/9666.5365.7976.7999.8897.5572.B336.6122+
 -  Step-by-step instructions for solving  Puzzle 23, (269/369)   Diff: 48/9999.9321.1135.3422.1122.2599.5596.8999+
 -  Step-by-step instructions for solving  Puzzle 24, (276/369)   Diff: 48/9979.9999.72A2.1121.3354.22B3.4324.6567+
 -  Step-by-step instructions for solving  Puzzle 25, (269/369)   Diff: 49/9.852C.A221.1213.1B55.4799.9995.3499.74B2+
 -  Step-by-step instructions for solving  Puzzle 26, (271/369)   Diff: 49/9.632C.1245.5433.7556.7769.7889.6899.8999+
 -  Step-by-step instructions for solving  Puzzle 27, (272/369)   Diff: 49/9.8644.34D5.21B3.1214.6548.52C1.2123.3A33+
 -  Step-by-step instructions for solving  Puzzle 28, (274/369)   Diff: 49/9.9845.2C23.2364.B11A.1248.8985.4A43.1121+
 -  Step-by-step instructions for solving  Puzzle 29, (274/369)   Diff: 49/9.8231.121A.2225.4112.4899.9989.7462.4699+
 -  Step-by-step instructions for solving  Puzzle 30, (264/369)   Diff: 50/99.5788.7776.72A1.21B1.1A13.3467.8963.3437+
 -  Step-by-step instructions for solving  Puzzle 31, (265/369)   Diff: 50/98.7535.3222.1124.4443.53D2.A135.8999.9999+
 -  Step-by-step instructions for solving  Puzzle 32, (267/369)   Diff: 50/99.9984.231C.7994.2333.5245.5789.9852.1AA1+
 -  Step-by-step instructions for solving  Puzzle 33, (270/369)   Diff: 50/99.9763.4683.2363.54D7.3498.4224.4231.123D+
 -  Step-by-step instructions for solving  Puzzle 34, (271/369)   Diff: 50/99.9995.41D1.1B11.2132.1131.3222.3535.62D5+
 -  Step-by-step instructions for solving  Puzzle 35, (271/369)   Diff: 50/99.9993.4574.D873.2333.3333.6435.3121.1143+
 -  Step-by-step instructions for solving  Puzzle 36, (273/369)   Diff: 50/99.9664.1251.3212.2487.2C24.5557.5645.3699+
 -  Step-by-step instructions for solving  Puzzle 37, (274/369)   Diff: 50/99.8999.9744.641B.1122.3569.9876.1B24.6799+
 -  Step-by-step instructions for solving  Puzzle 38, (274/369)   Diff: 50/99.6C42.11B6.6463.4556.7974.6697.771C.4463+
 -  Step-by-step instructions for solving  Puzzle 39, (275/369)   Diff: 50/99.6533.4353.441C.3344.2334.5898.8999.9869+
 -  Step-by-step instructions for solving  Puzzle 40, (276/369)   Diff: 50/98.6535.8668.8996.5347.4697.3542.5321.2D48+