How many lines are needed to make exactly N squares? Solve for 1<=N<=15.
For example, to make five squares, six lines are needed (draw a 2x2 grid, to give four 1x1 squares and one 2x2 square.) But to make exactly four squares, seven lines are needed.
Easier Extension: What is the largest number of squares which can be drawn with M lines?
Source: Original.