Martin Gardner, «Hexaflexagons and Other Mathematical Diversions:
The First Scientific American Book of Puzzles and Games»
Univ. Of Chicago Press | ISBN 0226282546 | (Sept. 1988) | djvu | 3.4 Mb | 213 pages
The First Scientific American Book of Puzzles and Games»
Univ. Of Chicago Press | ISBN 0226282546 | (Sept. 1988) | djvu | 3.4 Mb | 213 pages