24.3.5 $\star$ * 64 points arranged in an 8 by 8 grid, how many lines are needed at minimum to separate them?
Parse: By drawing a straight line between any two adjacent rows or columns, the 64 points can be separated, totaling 14 lines.

On the other hand, the outermost perimeter (as shown in the figure) has 28 points. To separate these points, the lines drawn must intersect the boundary at least 28 times, but one line can produce at most 2 intersections, so at least 14 lines are required.
In summary, at least 14 lines are needed to separate these 64 points.