an interesting $polyomina$
Source: Iranian RMM TST 2021 Day2 P1
April 16, 2021
combinatoricssquare grid
Problem Statement
A polyomino is region with connected interior that is a union of a finite number of squares from a grid of unit squares. Do there exist a positive integer and a polyomino contained entirely within and -by- grid such that contains exactly unit squares in every row and every column of the grid?Proposed by Nikolai Beluhov