TOT 1999 Autumn AS2 marked points on a rectangle paper, folding
Source:
May 11, 2020
geometryrectanglefoldingcombinatoricscombinatorial geometry
Problem Statement
On a rectangular piece of paper there are
(a) several marked points all on one straight line,
(b) three marked points (not necessarily on a straight line).
We are allowed to fold the paper several times along a straight line not containing marked points and then puncture the folded paper with a needle. Show that this can be done so that after the paper has been unfolded all the marked points are punctured and there are no extra holes. (A Shapovalov)