@ARTICLE {, title = {On rotations of geometrical figures}, author = {Krech, Ireneusz}, journal = {Obzory matematiky, fyziky a informatiky}, year = {2014}, volume = {43}, number = {3}, pages = {21--24}, issn = {1335-4981}, abstract = {The paper presents some original solutions to a certain problem by rolling coins (circles) derived from a book by David Wells The Penguin Book of Curious and Interesting Puzzles, and also proposes several generalizations of the problem.}, }