My first post to this forum. I am an advanced beginner - I play on my Android phone, using the app Enjoy Sudoku. I play at the 'Difficult' level and usually finish the puzzles in around three minutes
I ran into a situation today that I do not understand and was hoping that some one could enlighten me. The image below shows the puzzle mid-way through:
To my eye, the four squares shaded green appear to be a unique rectangle, thus one needs to avoid a 'deadly pattern'. This suggests that one of the square on the right side of the rectangle needs to be a 1, making the square highlighted yellow-green an 8 - because if it were a 1, then the 'deadly pattern' emerges. I tried this approach, and it was wrong. To solve the puzzle, one needs to see the 'other' unique rectangle (shaded pink) and assign the value 2 to the top-left square of that rectangle. When following this route, the following is how the board looks just prior to being completed:
This pattern seems to go against the notion of avoiding a 'deadly pattern'. Would someone kindly explain why this doesn't violate that principal, and perhaps, suggest what I should be alert to in the future should this arise again.
p.s. It should be obvious that I am not well-versed in Sudoku terminology, so please consider that when you reply.
Many thanks!
p.s. Based on my viewing of a few topics in this section of the forum, many of you seem to be heavy-duty mathematicians. I am just an engineer, so please show some mercy.
