Draw 9 horizontal and 9 vertical line through a square
Source: 2017 Thailand October Camp 1.2
February 25, 2022
combinatoricslinesconstruction
Problem Statement
horizontal and vertical lines are drawn through a square. Prove that it is possible to select rectangles so that the sides of each rectangle is a segment of one of the given lines (including the sides of the square), and for any two of the rectangles, it is possible to cover one of them with the other (rotations are allowed).