Identify the figure of speech used in the expression: 'And some are loaves and some so nearly balls'

In the expression 'some are loaves and some so nearly balls,' the stones are directly equated with loaves and balls without using 'like' or 'as.' This direct comparison without comparing words is a metaphor. If 'like' or 'as' were used (e.g., 'stones like loaves'), it would be a simile. Personification gives human qualities to non-human things, and irony involves contradiction — neither applies here.