 Further refinements introduce “relevance” into Polger and Shapiro’s account. The very function shared by the two kinds that classifies them as the same in the realized science must be what is realized by different mechanisms that classify them as different in the realizing science. Further, the relevant differences in the realizers contribute to the sameness of function; the kinds are “not just differently different, they are differently the same” (2016: 75). Polger and Shapiro show that simple (camera) and compound eyes meet their fully revised “Official Recipe” for genuinely multiply realized kinds. They write: 