My procedure starts with filling the top-left box, not the top row. So it looks something like this after the third step: 12.. 34.1 .1.x ..1. From here x can be any of [2,3,4], and each yields exactly one solution!
Here is one possible way of generating all 12 solutions by 2x2x3 choices: 1. Fill the upper left box with 1-2-3-4 2. Choose where to put the 1 in the top right box (2 choices) 3. Choose where to put the 1 in the lower…
My procedure starts with filling the top-left box, not the top row. So it looks something like this after the third step: 12.. 34.1 .1.x ..1. From here x can be any of [2,3,4], and each yields exactly one solution!
Here is one possible way of generating all 12 solutions by 2x2x3 choices: 1. Fill the upper left box with 1-2-3-4 2. Choose where to put the 1 in the top right box (2 choices) 3. Choose where to put the 1 in the lower…