How can you plant seven straight rows of trees with six trees per row such that twenty-one trees are planted in total?

How can you plant nine straight rows of trees with three trees per row such that nine trees are planted in total?

(In reply to 9 rows, 9 trees by brianjn)

9 trees, and 9 rows of 3, but also 3 rows of 2, making a  grand total of 12 rows.  Is this really what the problem was seeking? It is certainly more pleasing to have any line connecting two points to also connect three points.

Posted by Richard on 2006-10-23 14:51:35