Because I need something happy, I'm sharing my very favorite description of an algorithm. Much appreciation to my networking teacher from 1st year for introducing me to the wonderful work of Radia Perlman, who designed some of the protocols that make up the backbone of the internet.
I think that I shall never see
A graph more lovely than a tree.
A tree whose crucial property
Is loop-free connectivity.
A tree that must be sure to span
So packets can reach every LAN.
First, the root must be selected.
By ID, it is elected.
Least-cost paths from root are traced.
In the tree, these paths are placed.
A mesh is made by folks like me,
Then bridges find a spanning tree.
If you wanna read the original paper, it's An algorithm for distributed computation of a spanningtree in an extended LAN.
Image Source: wiki: Spanning Tree Protocol