The government pays farmers a specific fee for each row of four trees that they plant. An enterprising, but dishonest farmer found a way of planting five rows of four trees using only ten trees. How did he do it?
The farmer planted the ten trees in the shape of a star to get five rows of four trees.
This problem has several answers. Reader qc1okay provided diagram A, below. Diagram B is a more symmetrical variation of that idea.