The Science Side of Tumblr - Image #708,046

Additional explanation: Nature is a lazy shit and wants to do things in the way that is fastest and uses up the least amount of energy. When liquids freeze, the process starts at multiple points within their mass, and forms branching shapes called "dendrites". The reason the dendrites have the shapes they have is to maximize surface area to volume ratio, keeping the freezing process going as quickly and easily as possible.