*Fourier series: code from https://www.youtube.com/watch?v=PP5ox7evg7o&ab_channel=SteveBrunton
*Discrete Fourier Transform of a 4-D signal
*Hadamard Transform of a 4-D signal
*Fourier series: code from https://www.youtube.com/watch?v=PP5ox7evg7o&ab_channel=SteveBrunton
*Discrete Fourier Transform of a 4-D signal
*Hadamard Transform of a 4-D signal