MathDB
TOT 062 1984 Spring S-O3 99 pieces 2x2 cut of from a 29x29

Source:

August 19, 2019
combinatoricscombinatorial geometrysquare table

Problem Statement

From a squared sheet of paper of size 29×29,9929 \times 29, 99 pieces, each a 2×22\times 2 square, are cut off (all cutting is along the lines bounding the squares). Prove that at least one more piece of size 2×22\times 2 may be cut from the remaining part of the sheet.
(S Fomin, Leningrad)