Re: FFS
The concept does not imply that there be multiple points, each of which are required for proper operation of the system, but multiple redundant paths, processes, structures etc, such that failure of any one does not compromise the system. Think of a physical mass being held up by chain of links, wherein a failure of any single link would cause the load to fall, and a multi-stranded cable, wherein the failure of any strand would continue to hold the load.