  Given a complex, separable Hilbert space $\mathcal{H}$, we characterize those
operators for which $\| P T (I-P) \| = \| (I-P) T P \|$ for all orthogonal
projections $P$ on $\mathcal{H}$. When $\mathcal{H}$ is finite-dimensional, we
also obtain a complete characterization of those operators for which
$\mathrm{rank}\, (I-P) T P = \mathrm{rank}\, P T (I-P)$ for all orthogonal
projections $P$. When $\mathcal{H}$ is infinite-dimensional, we show that any
operator with the latter property is normal, and its spectrum is contained in
either a line or a circle in the complex plane.
