Problem

Source: Brazil Cono Sur TST 2024 - T2/P4

Tags: polynomial, Translation



In the cartesian plane, consider the subset of all the points with both integer coordinates. Prove that it is possible to choose a finite non-empty subset S of these points in such a way that any line l that forms an angle of 90,0,135 or 45 with the positive horizontal semi-axis intersects S at exactly 2024 points or at no points.