Here's a page about knight's tours, for those who've never heard of such a thing:
The Knight's Tour (http://www.borderschess.org/KnightTour.htm) - Dan Thomasson
Two similar closed centrosymmetric tours (http://www.borderschess.org/WFristoe.htm)
Here's what Centrosymmetric (http://en.wikipedia.org/wiki/Centrosymmetric) means.