In a lab in Atlanta, thousands of yeast cells fight for their lives every day. The ones that live another day grow fastest, reproduce quickest and form the biggest clumps. For about a decade, the cells have evolved to hang onto one another, forming branching snowflake shapes.
These strange snowflakes are at the heart of experiments exploring what might have happened millions of years ago when single-celled creatures first banded together to become multicellular. That process, however it went down, eventually resulted in unwieldy, fabulously weird organisms like octopuses and ostriches and hamsters and humans.