The V-Flex, Triangle Orientation, and Catalan Numbers in Hexaﬂexagons
Contribution to Book
Martin Gardner in the Twenty-First Century
Regular hexaflexagons mysteriously change faces as you pinch flex them. This paper describes a different flex, the V-flex, which allows the hexahexaflexagon (with only 9 faces under the pinch flex) to have 3420 faces. The article goes on to explain the classification of triangle orientations in a hexaflexagon and to give an example of flexagon combinatorics.
Iacob, Ionut E., T. Bruce McLean, Hua Wang.
"The V-Flex, Triangle Orientation, and Catalan Numbers in Hexaﬂexagons."
Martin Gardner in the Twenty-First Century, Michael Henle and Brian Hopkins (Ed.): 103-108: Mathematical Association of America (MAA).
doi: 10.5948/UPO9781614448013.014 isbn: 9781614448013