Can you plant 9 trees such there are 10 rows of 3 trees?
An example solution:
To construct:
- Start with a middle row of 3 equally spaced trees.
- Place a center tree in the top row at any distance from the center.
- Place a center tree in the bottom row at the same distance from the center as the top.
- The positions of the remaining trees are forced by extending the top and bottom rows parallel with the center row.