$$e^{i\pi }+1=0$$
The Lorenz Equations $$\dot{x} = \sigma(y-x)$$ $$\dot{y} = \rho x - y - xz$$ $$\dot{z} = -\beta z + xy$$
Maxwells Equations $$ \nabla \times \vec{\mathbf{B}} -\ \frac1c\frac{\partial\vec{\mathbf{E}}}{\partial t} = \frac{4\pi}{c}\vec{\mathbf{j}} $$
$$ \nabla \cdot \vec{\mathbf{E}} = 4 \pi \rho $$
$$\nabla \times \vec{\mathbf{E}}\ +\ \frac1c\frac{\partial\vec{\mathbf{B}}}{\partial t} = \vec{\mathbf{0}} $$
$$ \nabla \cdot \vec{\mathbf{B}} = 0 $$