I was reading Hank Green’s Tumblr today and he brought up a really interesting point:

In an interesting way, your digestive system is kinda not “inside” you. It is very much a tube of outside that runs through our insides. It’s a long and complicated tube, and our body has a lot of control over it, but we’re all kinda just long doughnuts with a mouth on the top and an anus on the bottom.

To the right is an illustration of the idea that we are topologically the same as a donut (and a coffee cup) from PeteSmif.

Even though I took an entire semester of Topology to get my math degree, I never once realized that I am just a topological donut with a mouth at one end and an anus at the other. Every bit of food that I eat is not “in” me. It is merely passing through my donut hole.

Something about this thought has changed me. In my Topology class, we talked about how a coffee cup and a donut are the same topologically, as illustrated in this picture from Arizona University:

I remember feeling strangely at peace with the idea that a coffee cup and a donut were topologically the same. I wonder why it was never brought up in class that humans share the same topology. I am humbled by this idea. I am a coffee cup. I am a donut. We are all one…