Writing in Aeon, Jamie Kreiner, associate professor of history at the University of Georgia, discusses distraction among monks and devices by which they could sharpen their attention, and in this case, their memory:
Say that you wanted to learn the sequence of the zodiac. Thomas Bradwardine (a 14th-century university master, theologian and advisor to Edward III of England) suggests that you imagine a gleaming white ram with golden horns, kicking a bright red bull in the testicles. While the bull bleeds profusely, imagine that there’s a woman in front of it, giving birth to twins, in a gory labour that seems to split her up to her chest. As her twins burst forth, they’re playing with an awful red crab, which is pinching them and making them cry. And so on.
I suspect Master Bradwardine had some issues he hadn't worked out yet.