The number comes from a simple game of trees—meaning the charts used in graph theory. In this game, you make a forest of trees using seeds.

The Yule tree graph The Yule tree is a graph with one edge coming in and two edges coming out of each branch-point. The branches represent the time periods between the evolution of new species.

More About the Game of Trees Discover the Enormity of the Number TREE (3) In this game, different colored seeds are used to make a “forest” of trees, or branching graphs.

Thanks to a team of scientists, there's a new "tree of life" showing the ancestry of millions of different species dating back to the beginning of the planet. The team, led by Karen Cranston of ...