Beautiful Designs Made from Two Knights' Tours
Two knights are placed on the empty chessboard and move according to the rules of chess. For a double knights' tour, one or the other of the knights must visit each square exactly once. In these variants, boards with a wide variety of shapes are used instead of a standard chessboard. Some solutions present very beautiful designs.
Snapshot 1: a graph made from problem 1
Snapshot 2: a board for a variant of the knight's tour
Snapshot 3: a solution for the problem
For the details of this article please see the following reference.
R. Miyadera, Y. Kakoi, N. Saida, K. Takeshima, Y. Ohishi, H. Matsui, T. Yamauchi, T. Kajimoto, K. Yoza, A. Hyogu, Y. Nakagawa, N. Totani, and D. Minematsu, "Beautiful Designs made from the Knight's Tour," Visual Mathematics: Art and Science Electric Journal of ISIS-Symmetry [online], 2007.