One of the most fundamental concepts in modern math is that of a 'manifold'. Manifolds come up everywhere -- differential geometry, general relativity, machine learning, just to name a few. But when I first encountered them, I found the definition technical and unintuitive.
'I am the silence that is incomprehensible and the idea whose remembrance is frequent. I am the voice whose sound is manifold and the word whose appearance is multiple.' - The Thunder, Perfect Mind
