University Studies 3-Fall 2013-Aftermath Sixth meeting (November 7) 

Original Puzzle from Gordon's book #73 (image1)

The next image shows the progress after supposedly implementing three "Gordonian rectangles". However, there is a mistake. Can you correct it and finish the puzzle? (For the record, I identified Gordonian rectangles at the following cells: 55,58,65,68 and 38,39,48,49 and 16,17,36,37. However, this may not help you since, as we noticed in class, there seems to be a mistake)

Puzzle #73 after implementing three "Gordonian rectanges". Needs to be corrected, as noted above. (image2)

Gordon's book, chapter 8, part 1, pp 59-63 (pdf file)

Gordon's book, chapter 8, part 2, pp 64-68 (pdf file)

Gordon's book, puzzles, pp. 57,69,70 (handed out in class) (pdf file)

My notes for the examples in chapter 8 of Gordon's book, 3 pp (Examples 17-23) (pdf file)

Puzzle 70 (not done in class) exhibiting two X-wings

Puzzle 70; original puzzle (original puzzle)

Puzzle 70; after basics and with pencil marks for candidates (with pencil marks)

Puzzle 70; Notice the X-wing at rows 6 and 8 involving the integer 5 (first X-wing)

Puzzle 70; Notice the X-wing at rows 3 and 7 involving the integer 6 (second X-wing)

Puzzle 70; Bullseye! The solution is easily obtained (solution)