MathDB
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 11 cm are nailed to a white plane with a nail of thickness 0.10 . 1 cm so that they form a black polygon. Can it happen that the perimeter of this polygon is 11 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 00 (a point ) . (c) Several black squares of side 11 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 100000100000?
(Hungarian Folklore)