The Non-Zero Differences Puzzles
In the following triangle, each number below the first row is computed by
taking the difference (absolute value) of the two numbers immediately above
it. The object of this puzzle is to fill in the top row with digits from 1 to
9 so that there are no 0's in the entire triangle. Note that the two 3's in
the triangle are already in position, and cannot be changed. The upper right
hand number is computed for you automatically, so you only need to find 8
digits. There is only one solution to this puzzle, and it can be found using
logic rather than trial and error.