Topologically speaking, your body is just a fancy donut with 13 holes! The digestive tract creates one continuous tunnel from mouth to... exit, making us technically a torus. Add in the tear ducts, nostrils, and other biological plumbing, and congratulations—you're basically walking Swiss cheese according to mathematicians. Next time someone calls you "well-rounded," just tell them it's your genus number talking!
For the uninitiated, in topology (the mathematical study of shapes), a donut and a coffee mug are identical because they both have exactly one hole. The "genus" is just fancy math-speak for "how many holes does this shape have?" So humans having genus 13 means we're basically the fanciest, most complicated donut at the bakery!