I find it much easier to compare their new "a generation" to strings of Christmas lights. You start with your first string, and if it doesn't quite reach where you need it, you connect another. This is where the two strings intersect--the prongs in the plug have to extend into the socket of the preceding string. If you still run short, you attach another set of lights. And so on--for obvious reasons, I do not recommend doing this with anything but commercial quality LED lights because you will blow a fuse with anything else.
Now, when the first generation falls short of where you need it, you simply connect another. Again, the generations intersect because the first one is right at the instant of death when the second in the string is just being born (like the prongs of one set connecting the socket in the preceding set). Since each "generation" ends with another socket and starts with a plug, this process can go on forever--as a bonus, there are no fuses to blow.