 Codes of this type were first described by William H. Kautz in the late 1950s; since then, there has been much research on finding the code with the largest possible number of codewords for a given hypercube dimension.Yet another kind of Gray code is the single-track Gray code (STGC) developed by Norman B. Spedding and refined by Hiltgen, Paterson and Brandestini in "Single-track Gray codes" (1996).The STGC is a cyclical list of "P" unique binary encodings of length n such that two consecutive words differ in exactly one position, and when the list is examined as a "P" × "n" matrix, each column is a cyclic shift of the first column.