Considerthe Red ball in Fig. 2a. Suppose Blue is for hoop 1, and let us suppose that Red has been rushed [to the hoop] by Blue, but has come to rest behind hoop 1, and what is more, it is close behind hoop 1 and very near the centre line. Now somehow, Blue has to take croquet from Red thereby getting to the other side of the hoop so that Blue can run the hoop.
If Red were off the centre line then Blue might try taking off as shown in Fig 2b but this is clearly doomed to fail.
Another approach (and this is probably the most common) is shown in Figs 2c, 2d and 2e where both balls are made to run through the hoop and then Blue in its continuation stroke runs its hoop. But alas, as so often happens, Blue ends up wired from Red and has no roquet after making its hoop.
Fig. 2f shows the neat way of solving this problem. The "vee" is lined to just miss the hoop leg and a gentle stroke is played. Blue goes through the hoop, Red being displaced slightly. Blue then runs its hoop and roquets Red in the next stroke. It needs a little practice but it is quite simple really.