Issue No. 07 - July (1970 vol. 19)
M. Cohn , Sperry Rand Research Center
To seek the origins of Gray codes is to peer farther into the past than 1947. As mentioned in our note, the structure of our counter was suggested by the ""Chinese rings"" puzzle; the codes themselves can describe solutions to the ""Tower of Hanoi"" puzzle (see our ). More recent uses of the unitdistance principle may also be found.<sup>4</sup>
M. Cohn, "Authors' Reply<sup>3</sup>," in IEEE Transactions on Computers, vol. 19, no. , pp. 654, 1970.