The web resource on numerical range and numerical shadow

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Shadows of family of matrices $$M_4(\phi)=e^{i\phi} \begin{pmatrix} 1&0&0&1\\ 0&i&0&1\\ 0&0&-1&0\\ 0&0&0&-i \end{pmatrix},$$ with $\phi\in[0, 2\pi]$. Upper and right plots present marginal distributions of real and imaginary part corresponding to shadows of hermitian and anti-hermitian parts of $M_4(\phi)$.