A rat's neurons and macro structure in the cosmos are totally unrelated...
But the same patterns do keep on popping up.
Hurricanes look just like spiral galaxies, although the arms in each are formed by entirely different physical process.
Lots of patterns like that seem to repeat, although it is easy to understand when their causes are similar, it is fascinating when similar shapes arise for totally different reasons.
In mathematics, you keep seeing the same patterns over and over again, like sine waves, and they also pop up all over nature.