Place 9 balls ("o") in the intersections of the grid below to achieve 10 straight lines, each line containing 3 and exactly 3 balls. You may assume, if you need, that each cell is a perfect square.
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+---+---+---+---+---+---+---+---+
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+---+---+---+---+---+---+---+---+
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Once again I had written and submitted a comment as a reply (to Leming's posting) only to have it disappear. Apparently that does not work consistently, so I will try again as a separate comment.
Solving this puzzle depends upon the interpretation. I assume (1) that "in the intersections" means ON the intersections, not within the cells, (2) that "to achieve 10 straight lines" means that the solution must place the nine balls on EXACTLY 10 lines (neither more nor less), and (3) that each line has 3 balls (neither more nor less). The spec that each is a perfect square I assume is to allow lines which may pass through cells at any angle.
I hope we may agree that ANY TWO points determine a line, and that a line (not a line segments joining balls) always must be extended to the perimenter and intercept it at two points unless the two points lie on the same edge.
Given that interpretation, several lines in Leming's diagram apparently have only two balls. This would seem to betoken an interpretation that "achieve 10" means "achieve 10 or more" lines. I must admit that I do not see a solution given my reading of the puzzle, but there are probably many if there is no restriction of the number of lines.
What say ye all?
Ambiguous
