TOT 2000 Autumn AS6 black squares of side 1 lie on a white plane
Source:
May 11, 2020
combinatoricsColoring
Problem Statement
a) Several black squares of side cm are nailed to a white plane with a nail of thickness cm so that they form a black polygon. Can it happen that the perimeter of this polygon is km long? (The nail is not allowed to touch the boundary of any of the squares . )
(b) The same problem as in (a) but with a nail of thickness (a point ) .
(c) Several black squares of side cm lie on a white plane so that they form a black polygon (possibly having more than one piece and/ or having holes) . Can it happen that the ratio of its perimeter (in centimetres) to its area (in square centimetres) is more than ? (Hungarian Folklore)