An interesting symmetry that is very important to biology and engineering concerns scaling.

Have you ever made a giant paper airplane out of a big piece of paper, using the exact same folding method you use for a normal-sized airplane ?

They're exactly the same.... Well, not really....

They're both made of paper fibers, which are made of a molecule called cellulose, which is made of long strings of sugar molecules, which are rings of carbon atoms.

And the atoms didn't change size when you made a bigger airplane...