Steve,
There are histories about most of the traditional blocks and flyfoot is no exception. I found the following quote at
http://www.50connect.co.uk/index.asp?main=http%3A//www.50connect.co.uk/50c/articlepages/leisure_index.asp%3Fsc%3Dartsandcrafts%26aID%3D141 58
One heritage pattern is known alternatively as the 'Flyfoot Swastika' or the 'Devil’s Puzzle', which shows that the icon of the swastika was used long, long before it was adopted as the symbol of the Nazi party in Germany.
I personally will never make the flyfoot block but I'm sure our grandmothers of years back probably did! Just mark it down to a history lesson.