Temporary

Fourier series, square wave

$f(x)=\frac{c}{L}+\frac{2}{\pi }\sum _{n=1}^{\mathrm{\infty }}\frac{(-1{)}^n}{n}\sin \frac{n\pi c}{L}\cos \frac{n\pi x}{L}$

$f(x)x2c10L2L$

Result: