Picture fractal which is everywhere in Nature.

Fractals are complex in their mathematical formulation. Yet that complexity is what makes them beautiful and pure magic of Nature.

I believe that we should strive to simplify complexity in a way that makes every concept beautiful.

Let's imagine that you are a great music composer. You may use complex compositions to create your best music. Yet when I hear it, all I see is the beauty of it, not the complexity of the process.

I hope that this helps clarify the meaning behind "Complexity is in the beauty of simplicity."