I never understood how multiple electrical frequencies can be in a copper cable. I always thought they must merge and therefore it must be impossible to find t

I never understood how multiple electrical frequencies can be in a copper cable. I always thought they must merge and therefore it must be impossible to find the right set of original frequencies and their strength. Then I learned about the Fourier transform in this beautiful video: https://youtu.be/spUNpyF58BY https://youtu.be/spUNpyF58BY