Since the focus of this poem rests largely on the poppy's petals, they get compared to a lot of different stuff – but most often, Hughes frames the flower in terms of its shape, which is distinctly cup-like. The idea of flower-as-cup gives rise to a couple of different container comparisons, all of which add layers of meaning to the poem – enough, in fact, to make the theme become allegorical. We'll go through them here.
- Lines 4-5: First container, and it's already a multi-layered metaphor. First off, the words "fractured goblet" invoke the shape of the flower itself, perched as it is on top of a thin stem and broken as it is by being made up of several distinct petals. The "drunken" bit conjures up images of intoxication (so does "goblet" for that matter), which is connected to the flower's eventual use as an opiate.
- Lines 13-14: This container is a crucible. In industry, a crucible is a cup-shaped tool used to heat stuff – everything from chemicals to steel. The important part is that a crucible is used with extremely high temperatures. Otherwise, it's just a cup. So, in addition to the flower being compared to something that holds intoxicating liquid, it's also a container that hold things that are excruciatingly hot. We're building danger here.
- Lines 18-20: Two containers for the price of one, here, and this time they're not alluding to the shape of the flower. Instead, we have metaphorical reference to the "closed container" that is the flower's eventual seed-pod. Note also that "coffin" and "cradle" are alliterative – bringing into further relief how closely this poem ties birth to death.